CPU's and Memory

[Direhit]

This section is dedicated to the FAQ's concerning processors and memory.

[Direhit]

Q: Help! I don't know if my memory is faulty or not! I think these errors I'm getting are due to my memory, but I don't know!

A: The first thing to do is to set your memory timings in your BIOS to the most conservative settings possible. If you are able to run your system stably with these conservative settings, then the odds are, that you were trying to use too aggressive of a memory timing. If these settings work, then leave everything else alone, and be happy.

If that doesn't help your stability, then test your memory with a simple method:

Despite its crude nature, himem.sys is actually a pretty good memory tester. Create a bootable floppy disk using DOS, Win 95, or Win 98, using this command:

format a: /s

Then find a file called "himem.sys" on the DOS, Win 95, or Win 98 computer. Copy it onto your bootable floppy. Type the following command from a DOS prompt:

edit

and type this line in the editor:

device=a:\himem.sys x=C700-C7FF

Save this file as a:\config.sys

I specifically exclude the C700-C7FF becuse quite a few video cards, even these days, occupy that space of memory.

Now, reboot your computer with this bootable floppy, and himem.sys will do a memory test. It's actually pretty decent when it comes to finding faulty memory.

Note: This process works for any computer, regardless of operating system, as the OS required for himem.sys is already on the floppy disk.

If you want actual memory testing programs, try:

http://www.memtest86.com
http://www.docmemory.com/PAGE/products/doc/docinfo.asp

At this time, memtest86 version 3.0 seems to be the most thorough, and easily used. You can either download the executable that automatically makes a bootable floppy disk for you, or you can download the ISO and create a bootable CD-ROM. Either way, just boot up your system using either the newly created floppy or CD, and sit back while the tests run.

[Direhit]

Q: I am going to get a new motherboard / memory combination, but I don't know which one is going to be ideal for me.

A: Out of the three types of memory currently available (SDRAM, DDR SDRAM, RDRAM), SDRAM is going to be the slowest. Even though its latency is much lower than RDRAM, its bandwidth is too limited. RDRAM, conversely, is going to give the greatest bandwidth, but comes with a terrible latency penalty. DDR SDRAM is essentially the same as SDRAM, except better bandwidth.

Now that wider bandwidth dual channel solutions are widespread for DDR platforms, it simply makes no sense to go with a RDRAM-based motherboard. Furthermore, buying a RDRAM-based system is a dead end.

[Direhit]

Q: My CPU seems to be running at a hot temperature. Should I be concerned? What can I do about it?

A: The first thing I recommend to someone who buys one of today's powerful CPU's is to get a good quality heatsink / cooling fan (yes, the ones that come with the retail chips are good enough), and to remove the thermal pad with a razor blade and cleaning off the metal contact surface of the heat sink with some rubbing alcohol.

Once your heat sink surface is clean, put a plastic bag over your hand, and take a dab of Arctic Silver III / Antec Silver Reference thermal compound about half the size of a BB, and spread it evenly all over the heat sink surface with your finger that is covered. Don't let any of your skin oils touch the silver compound, as it will interfere with heat conductivity. Once you have done this, proceed to the next step.

Put a dab of either Arctic Silver III or Antec Silver Reference thermal compound, about half the size of a BB, and spread it evenly over the contact surface (the raised portion) of the CPU, using a CLEAN razor blade. Do NOT use your finger, as the oils will contaminate the compound, and interfere with heat conductivity.

Then, clamp on the heat sink (carefully).

The micronized silver compounds I mentioned above do a better job of conducting heat than the polymer-based compounds that come with the heat sinks. Even though you are only putting a thin film on there, it does a remarkable job.

Typically, with a good heat sink and cooling fan, along with the use of the micronized silver thermal compounds, I typically see AMD Athlon XP chips up to the 1900+ spec run at a relatively cool 45 degrees Centigrade. The newer core ones, despite their higher speeds, operate at slightly lower temperature, all things otherwise being equal.

In general, I do not worry about CPU overheating unless the temperature creeps above 60 degrees Centigrade. I never see this happening, though, when the above methods are used.

[Direhit]

Q: I wanted to get an AMD CPU, but some guy says that I should go with only Intel. What should I get?

A: These days, the CPU has less and less to do with your system performance. Once you get a sufficiently powerful CPU, it's more of a matter of getting a good video card to go with it.

If you have an Athlon XP, Athlon 64, or Pentium IV CPU, then you should be able to run today's games (and tomorrow's) quite nicely, provided that you got a good video card, a decent motherboard, and use good quality DDR SDRAM. Read the FAQ.

There are some cases where you may want to go with a Pentium IV:

If you are using programs that are optimized for SSE2 only, the Pentium IV and Athlon 64-class CPU's offer SSE2. If you don't know what SSE2 is, then you are probably not affected by this.

If you are using programs that are optimized for SSE3, then the newer Pentium IV and Athlon 64 CPU's (Venice cores and later) are probably the best solution for you.

The only current CPU's that go with Rambus DRAM motherboards are Intel Pentium IV CPU's. While there were some Rambus-based motherboards for the Pentium III, they used the awful i820 chipset, which I would only wish on an enemy. There is no more real benefit in going with a Rambus platform.

The above examples cover a very minute percentage of computer users out there. Even hard-core gamers are not really part of the above mentioned users.

[Direhit]

Q: What KIND of DDR SDRAM should I get, then?

A: Right now, the best bang for the buck comes from PC3200 / 400 MHz DDR SDRAM. The cost of it is virtually identical now to the older PC2700 / PC2100 memory, and it makes no sense to buy PC2700 or PC2100 memory unless you can get some at a very cheap price.

If you want to get PC3200 memory, then do a bit of research first. The JEDEC has finally released a standard for PC3200 / DDR 400 memory. When you order your memory, make sure that the PC3200 memory complies with the JEDEC standard.

[Direhit]

Q: Well, then, what companies sell genuine PC3200 / DDR400 memory that conforms to the JEDEC standard?

A: Two companies that I know, for sure, abide by this standard:

Crucial Technologies: http://crucial.com
Mushkin: http://www.mushkin.com

Given that Kingston just released an announcement (14 Apr 2003) that they would be offering JEDEC-spec PC3200 modules, I would wait for another month before trusting them. Given that they even have PC3500/DDR433 memory listed, when there is no such JEDEC-spec at this time, only increases my skepticism.

[Direhit]

Q: Why do workstation applications tend to run better on an Intel Pentium 4 versus an Athlon XP / 64 / FX CPU?

A: The answer can be broken down into parts.

1) The newer Intel Pentium IV CPU's, as well as Athlon 64 (and FX) use SSE, SSE2, and SSE3, instructions, for which many workstation applications are optimized. The AMD Athlon XP uses SSE and 3DNOW! for its instructions. While the Athlon XP does benefit from SSE, it is not capable of executing SSE2 / SSE3 instructions natively, which can hurt its performance in applications that are optimized for SSE2 / SSE3.

2) Memory bandwidth is important, as stated earlier. Dual DDR channel boards will be better than single channel DDR boards. Keep in mind that all Socket 754 Athlon 64 boards are single channel, and all Socket 939 Athlon 64 boards are dual channel, since the memory controllers are built into the CPU's.

[Direhit]

Q: Now that the AMD Opteron is out, should I get one now?

A: As with all newly released technologies, the price premium is rather high at this time. The 1.8 GHz Opteron looks to be an excellent performer in 32 bit applications, as it is able to beat out the Pentium IV 3.0 GHz chip in just about almost all applications, and working at a cooler temperature.

Then why am I recommending that you wait? First of all, you are going to have to shell out 300+ for a 1.4 GHz CPU. Secondly, the prices of the motherboards start at 500 dollars for the Microstar board (the least expensive one at this time).

These boards aren't going to come cheaply, since they are mostly made with 8-layer construction, and again, they are so new, that only the most wealthy can afford them.

So, at this time, if you have some money burning a hole in your pocket and want an Opteron, just stick it in a safe investment, and wait for a few months. Otherwise, if you must have something now, just go with one of the systems I mentioned in the FAQ, as you can have all sorts of wonderful conveniences with multiple computers in your home.

[Direhit]

Q: What companies sell memory that I can trust?

A: That depends on what kind of memory modules you need.

For 184 pin DDR SDRAM modules and 168 pin SDRAM modules (PC100 or PC133):

http://www.crucial.com
http://www.mushkin.com
http://www.kingston.com

Of course, http://www.newegg.com sells all of the above, and sometimes at a slightly lower cost. Always check with both companies.

For notebook memory:

http://www.crucial.com
http://www.kingston.com
http://www.ramjet.com

I would strongly recommend, that if you buy a laptop computer, just get the bare minimum memory from the manufacturer, and buy extra memory from some place such as Crucial. As an example, IBM wants 50 dollars for a 128 MB DIMM for a R40e Thinkpad laptop. A similar DIMM that is guaranteed to work in that same laptop is only 22 dollars.

For obselete memory (EDO, FP):

http://www.crucial.com
http://www.ramjet.com
http://www.kingston.com

[Direhit]

Q: I just installed one of the more recent Athlon XP CPUs in my motherboard, and I am getting some errors, even though I know the CPU is perfectly good. What's going on here?

A: Many motherboards will need a recent version of the BIOS flashed onto them, especially when it comes to fully supporting the "Barton" line of CPU's. This is also true of the more recent Thoroughbred CPU's (2400+ and higher).

It's entirely possible that your motherboard will not support the faster CPU's. Consult the website of your motherboard manufacturer; they should have a listing available in their tech support pages showing what CPU's can be used with your motherboard.

[Direhit]

Q: My motherboard is a Soyo P4X400 Dragon Ultra, and I am trying to use a 1 GB DIMM in it. I know the DIMM is good, since it worked in another machine, and my motherboard works fine with 512 MB modules. Will this memory work somehow?

A: The Soyo P4X400 does not handle 1 GB modules at all, despite the company claims that it will. It appears that this particular motherboard, although of good quality, does not have the ability to handle such a load.

As the folks from Mushkin put it:


* The load on the clock generator as well as the address and command bus of the memory controller increases in a linear fashion with higher memory configurations.
o Each chip has a certain input capacitance and if the number of chips is doubled, the amount of work that has to be done by the controller will be doubled as well.
* Higher load, in turn, will slow down the signal. Therefore, by definition, higher system memory configurations will have to run at lower frequencies than low density configurations.
* High quality components will be able to partially ameliorate this problem, however, the tuning of the overall chipset and memory timing will be the most critical factor for whether the system will be able to handle e.g. 2 GB of total memory.
o Everybody knows about CAS latency but there are other factors like setup and hold time, Read Latch Delay, Data I/O strobe delay (DDR only) and drive strength adjustments that need to be precisely tuned.
* Because of the competition, every manufacturer tries to squeeze the maximum performance out of their boards which is potentially counterproductive for handling high memory loads.
o Try to envision a horse trailer being pulled by a Porsche, how long will it take until the clutch burns?

[Direhit]

Q: I have noticed that various vendors sell OEM and Retail Boxed versions of the same CPU. Is there any real difference between the two?

A: Yes. A retail boxed CPU comes with a three year warranty from Intel or AMD, and also comes with a decent heat sink and cooling fan, along with some thermal compound.

An OEM CPU is just the CPU itself, no heat sink, no thermal compound. Warranties are entirely up to the discretion of the vendor. Some will give you 10 days, others 14-15 days, some will give 30 days, and others may even give you one year if you purchase a heat sink from them. It is up to you, the buyer, to read the fine print on what exactly this OEM CPU will have in terms of a warranty.

OEM CPU's will be cheaper than retail boxed ones, as expected, although if you can find a retail boxed CPU for only a few dollars more than the OEM, go with the retail boxed CPU instead, as the warranty and the heat sink are certainly worth it.

[Direhit]

Q: My computer needs Rambus memory, and I was wondering what kind I should get?

A: This is under construction...

Rambus memory is only made by a few manufacturers, so your choices are somewhat limited here.

If you have a Pentium III computer that uses Rambus memory, then that means that you are using a motherboard based on an i820 chipset. Don't waste your money here, since this chipset was poorly crafted, and you really wouldn't see any performance gain.

If you have a Pentium IV computer, then you should follow a few simple precautions:

1) Do not get the 45 nanosecond memory. At the end of each individual memory chip, you will see a -32, -40, or -45, which indicates the speed of the memory. If you attempt to use -45 RDRAM, then you will either get terrible system stability, or your system will perform as if it were in PC600 mode.

If you are using a 533 MHz FSB system, then stick with the PC1066 memory, although the best of the PC800 -40 memory modules may work decently. With the prices being only slightly different between the two speeds, it makes sense to get the faster PC1066 memory anyways.

2) Be sure of what your motherboard uses, whether it's 184 pin 16 bit RIMM's, or if it can take the 232 pin 32 bit RIMM's.

[Direhit]

Q: I saw some PC3500 and PC4000 memory available for sale. Should I buy this memory right now?

A: As of this date (28 Aug 2003), the JEDEC has not specified any standard faster than the PC3200 standard (DDR 400). Anyone selling you PC3500 (or faster advertised) memory is either ignorant of the facts, is pulling your tail, or is taking a risky gamble that it will work in future systems that require such memory (not a guarantee; it could work, or it might not).

[Direhit]

Q: I am trying to install Windows 95 on a computer built with a fairly recent AMD CPU. I keep running into error messages when running applications. I don't get this problem with an Intel CPU of any kind. How can I fix this?

A: You can fix this bug in Windows 95 with the following critical updates:

http://www.microsoft.com/windows95/downloads/default.asp

[Direhit]

Q: I have my DDR Voltage setting in my BIOS set to "Auto" and the motherboard keep using a 2.80 volt setting. Is this OK?

A: I've seen people with boards who were running their DDR memory at 2.8 volts for many months now, and they haven't incurred any damage to their memory. However, the correct setting for your DDR SDRAM is 2.50 volts for most DIMM's, and 2.60 volts for some of the recent DIMM's.

[Direhit]

Q: Are the new thermal compounds that use Carbon Black any good? I heard that they are supposed to be better than anything else.

A: Yes, and no. It is true that Carbon Black has a greater potential for heat conductance, but for Carbon Black to attain optimal thermal conductivity, it must be exposed to a higher amount of pressure, since the particles do not fill in the spaces nearly as well as the better heat sink compounds.

To attain this amount of pressure would probably end up damaging your CPU core. Not worth it.

Also, Carbon Black-based thermal compounds are rare, and expensive. It makes no sense to spend all that money on a novelty, when the better compounds, such as Antec Silver Reference Compound, Arctic Silver III or Arctic Ceramique, are easily available, and at much cheaper prices.

For a more thorough explanation:

http://www.lostcircuits.com/advice/carbon_black/

[Direhit]

Q: OK. I went ahead and bought some Arctic Ceramique. Does this work in the same way that Arctic Silver does?

A: No. Ceramique is physically more viscous, and is applied a bit differently, compared to Arctic Silver.

You should still treat the heat sink surface in the same way you do with Arctic Silver, but for the CPU core itself, just take a small dab of Ceramique, about 1/2 the size of a BB, and apply the heatsink directly on top. The pressure will spread it out automatically.

While you are putting on the heatsink, you may want to twist it a wee bit, just to even out the spreading a bit more.

A detailed, illustrated instruction is found here:

http://www.arcticsilver.com/ceramique_instructions.htm

[Direhit]

Q: How do I get the old heatsink compound off my CPU and heatsink?

A: The phase change thermal pads vary in composition, so what works for one, may not necessarily work for another. Arctic's recommendations have worked well for me, and these are my suggestions as to what works easily with their methods:

I've found that xylenes (available at any Ace Hardware store) are the most versatile, being able to cover the broadest range of phase change compounds, and is able to remove Antec Silver Reference compound just with some scrubbing with an old toothbrush. Only use xylenes for the heat sink, or the CPU surfaces that are not part of the core.

Acetone is almost as versatile, and can be used on both the heat sink as well as the CPU core. Also easily available at any decent hardware store. Use an old, clean toothbrush, and scrub gently in circles. Complete the cleaning with a quick wipedown using 91% isopropyl alcohol. Make sure you use solvent-grade acetone, and NOT nail polish removers, since these contain non-volatile compounds that will adhere to the surfaces, interfering with heat conductivity.

91% Isopropyl alcohol, available at any Wal-Mart in the medicinal area, also works well for many compounds, and is the solvent of choice when trying to remove Arctic Silver. It will also easily remove Arctic Ceramique, although why you would want to remove it is a question in the first place, unless you didn't apply it properly. Isopropyl alcohol is fine for both the heat sink and the CPU core, and is the friendliest solvent to work with in this case. Use an old clean toothbrush, and scrub lightly in circles. You can also use cotton swabs soaked in isopropyl alcohol.

If you don't want to bother with buying solvents, then just get Arctic's new heatsink cleaning kit, which consists of two mixtures of chemicals.

[Direhit]

Q: Where can I buy the Shin-Etsu phase change thermal compound? Is it sold under a different name?

A: The Shin-Etsu 7762 phase change thermal compound is sold by Coolermaster, part # PTK-001. Do not confuse it with Coolermaster's other thermal compound (which still works decently) # HTK-001, which uses Dow-Corning's 340 compound, instead.

In all honesty, though, using Shin-Etsu 7762 does not result in any better performance than Arctic Ceramique, and cleaning Shin-Etsu 7762 off your components is a difficult task, but those who insist on it will get it anyways...

[Direhit]

Q: Why doesn't Mushkin sell their "Green" level memory on their website anymore? I like using this stuff, since it's high quality, cheap, and stable.

A: Mushkin still sells their "green" tier of memory modules, although the sales of such are handled through their distributors. Yes, Newegg.com does carry it, and at a reasonable price.

Mushkin "Green" memory at Newegg still carries the lifetime warranty directly from Mushkin (best customer service in the game), and yes, even the refurbished Mushkin modules that Newegg sells, is still covered by Mushkin's excellent warranty, as long as you bought them from Newegg, or one of Mushkin's authorized dealers.

[Direhit]

Q: What are these new AMD CPU's called "Thorton's?" Can my current motherboard use them?

A: The Thorton line of AMD Athlon XP CPU's is apparently the same CPU as an AMD Athlon XP Barton CPU, but with only 256 K of L2 cache active. Apparently, AMD has finished selling off the remnants of their older Thoroughbred core CPU's, and have consolidated their production lines to produce Barton / Thorton CPU's.

Most motherboards should be able to take them, but you'll probably need a BIOS flash. No software patches for the operating system should be necessary, unless you're still thinking of running Windows 95.

[Direhit]

Q: Why won't my PC3200 memory work with an Athlon64 FX / Opteron motherboard?

A: AMD's specifications state that you must use registered memory modules. This invariably means that these are also ECC modules. When you shop for memory modules for an Opteron or Athlon64 FX, you'll be looking for registered, ECC modules.

While there are registered, non-ECC modules available, such memory modules are very rare, indeed, and not really any cheaper than their ECC counterparts. The bottom line is, that you must use registered memory modules for ideal operations.

If you have a REGULAR Athlon64 (non-FX), then your old PC3200, non-registered memory will work fine. Remember, though, Athlon64 systems based on Socket 754 operate in single channel memory mode only. Socket 939 Athlon64 systems can operate in dual channel memory mode.

[Direhit]

Q: I just bought some Crucial memory, and it works fine in one nForce2 motherboard, but not in another. What's going on here?

A: It's not an incompatibility. Read the sticker on your Crucial DIMM. Some of the later DIMM's are now labelled as 2.6V parts, as opposed to their 2.5V predecessors. You might not want to mix this RAM with the older 2.5V RAM, unless you feel comfortable in operating your RAM at 2.6V. For the most part, your 2.5V RAM should work fine at 2.6V, but as always, keep an eye on it.

[Direhit]

Q: I have a mini-tower ATX case that puts the power supply directly over the CPU. I have enough room to mount the heat sink and cooling fan and properly installed the heat sink compound, but I'm still badly overheating. What is going on?

A: Traditionally sized heat sinks need a bit of space between the cooling fan and the "ceiling." Odds are, that your cooling fan isn't able to effectively suck enough air to keep the heatsink cool, and what air it is taking in, is already pre-heated by the power supply.

The most efficient solution is to simply change your heatsink and cooling fan, to a lower profile one. If you do a search on 1U heatsink / cooling fan combinations, you will find many that will work just fine. These heatsinks are commonly used in 1U server cases, where space is very limited.

This method need not be expensive. While it's true that the premium JAG systems cost 40 bucks (give or take), you can still get a Speeze all-copper heatsink + cooling fan from Newegg.com for 13 dollars, and it will work quite nicely for most processors. I would strongly suggest replacing their heatsink phase change pad with a better thermal compound, such as Arctic Ceramique.

[Direhit]

Q: I saw some Mushkin memory for sale on sites other than Mushkin's main one, and was wondering if they would honor their lifetime guarantee?

A: I have received confirmation from Mushkin, that if you buy Mushkin memory from Mushkin themselves, or from one of their AUTHORIZED dealers (such as Newegg.com), then they will honor the lifetime warranty, provided that you are the original owner. Yes, this even applies to the refurbished Mushkin memory modules that you can buy on Newegg.com. Even though Newegg will not refund / replace them after the 15 day Refurbished Parts time period, Mushkin themselves will still honor the lifetime warranty. This is why I have Mushkin as one of my favorite memory brands.

If, however, you buy Mushkin memory from a non-authorized dealer, or if you buy it from some place like E-bay, the lifetime warranty does not apply.

[Direhit]

Q: I've heard that AMD's Athlon XP "Mobility" CPU's come multiplier unlocked. Is it really worth getting one of these?

A: Breaking from my normal protocol of discouraging overclocking, I am going to actually endorse it in this case. Yes, it is true, that currently, AMD's Athlon XP-M CPU's are multiplier unlocked, meaning that you can set your own multiplier.

These CPU's run at a modest 1.45 volts, and use a 266 MHz FSB setting. With a conservative voltage upping to 1.6 volts, you can easily have these CPU's running at 333 MHz, and an Athlon XP 2400+ Mobility CPU can be painlessly turned into an Athlon XP 3000+ CPU without any rise in CPU temperatures.

The best bang / buck is the XP 2400+ Mobility CPU, especially since it has 512 K of L2 cache built in.

[Direhit]

Q: What are these AMD "Sempron" CPU's that are coming out?

A:
AMD's Sempron CPU's are going to be the next wave of budget-minded CPU's. The first wave of Sempron CPU's will fit into Socket A motherboards used by the aging Athlon XP and Duron platform. It is not known whether the CPU's will have full SSE2 support, but there should be a decent chance.

The later released ones will fit into the same Socket 754 and Socket A motherboards as their Athlon 64 and Athlon XP cousins do, but are going to be crippled, and are NOT going to be 64 bit CPU's.
The Socket 754 CPU's, though, should have full SSE2 instruction sets built in.

[Direhit]

Q: Can you overclock the Athlon 64 mobility CPU's in the same way that you do with the Athlon XP mobility CPU's?

A: No. The Athlon 64 mobility CPU's have fixed multipliers. You can only overclock them by modifying the bus speed. Tread carefully...

[Direhit]

I have an Athlon XP CPU in my motherboard that is constantly overheating. The problem is that the power supply is so close to the top of the CPU fan, that it's not getting enough cooling. Is there a way to avoid this?

A: Typically, this occurs when people use mini-tower ATX cases that have the power supply stacked on top of the CPU area. While such configurations will fit, this will obstruct the air flow, and interfere with the heat sink's ability to cool down the CPU.

To correct this, turn off the computer, of course, and then remove the heat sink. Replace it with a heat sink with a low profile. Typically, the ones labelled for use in 1U situations, where space is at a premium, will work quite nicely. I recommend the Speeze system:

http://www.newegg.com/app/ViewProductDesc.asp?description=35-150-029&depa=0

Replace the heat sink compound that is on the heat sink, with something better, such as as Arctic Ceramique. I've had Athlon XP2500+ CPU's running with this heat sink / cooling fan in Enlight 7101 mini-tower ATX cases, and stay in the upper 40's.

[Direhit]

Q: Do I need an Athlon 64 FX to run my Socket 939 system in dual memory channel mode?

A: No. The "ordinary" Athlon 64 CPU's that are Socket 939 have dual channel memory controllers built into the CPU as well.

[Cobalt]

Q: What's all this I've been hearing about Dual Core processors?

A: The entire microprocessor industry has been having problems getting a single CPU clocked to higher frequencies. For those of you not entirely literate with the art of making a CPU, the problem, simply put, is the higher in frequency you clock a specific chip, the better your manufacturing must be to make the same amount of chips as you would at a lower frequency. As an example, a 2.4 GHz Prescott P4/AMD64 and a 2.6 GHz Prescott P4/AMD64 are the same exact chip, it's just the 2.6 is a better-quality chip, silicon-wise.

Intel has recently cancelled their release of the 4.0E Prescott Pentium 4 due to issues regarding heat output and yields. On the other side of the coin, AMD has shrunk their current K8 architecture [Athlon 64/FX/Opteron] down to 90nm from 130nm, bringing lower power consumption and some frequency headroom [up to 3 GHz]. However, as the prices for the new Athlon 64 FX-55 and Athlon 64 4000+ are both over 700 dollars a chip, even though AMD's K8 architecture is proving itself performance-wise, they cannot make their best CPUs for as cheap as they could a year ago.

The traditional response to hitting a barrier in speed of a chip is to redesign the architecture to be able to scale to higher clockspeeds, or shrink the manufacturing process, because shrinking the CPU allows it to be run at higher speeds using the same amount of power. Redesigning the architecture takes a long time and a lot of effort to do, and it's not a terribly effecient process, and the microprocessor industry just shrunk to 90nm from 130nm as the standard process for manufacturing, and shrinking to 65nm from 90nm is seen as being terribly difficult.

So, if we can't make it smaller, nor can we redesign the CPU, what can we do? We can take a page from the server market, have desktop systems with lower-clocked, easier to produce, and cheaper dual CPUs. If we can't get a 4.8 GHz chip, why not use two 2.4 GHz chips in a single system?

There are problems with dual-cpu systems. First, if you've seen any dual-cpu systems, no matter what CPU is in the system, they are unmistakably loud. Secondly, both CPUs will have to share the same resources - namely FSB/Hyper Transport lanes, etc. Thirdly, you have to use something that will utilize both CPUs at once, isn't that the point of having two cpus in a system?

To mitigate some of the negatives of having dual-cpu systems, Intel and AMD are developing dual-core processors. Simply put, these are CPUs that will plug into one socket on the motherboard and use one standard HSF [heat sink fan], like all of the ones you have seen today, but "under the hood" there will be two distinct cores on the CPU and both of the cores will attempt to execute [portions of] your code simultanouesly. Both companies have basically the same design strategy - both CPUs will have their own execution units, and caches [both L1 and L2], with an arbiter that takes the job of load-balancing and telling which core to do what work at what point in time. AMD does have the advantage here, the K8 architecture was designed with dual-core in mind, the "links" for dual-core are present and active in all current-day A64/FX/Opterons, it's just there is no second core on the die for the first core to "talk" with. Intel is in the process of designing a dual-core architecture.

From here on out, I will use the terms "Dual CPU" and "Dual core" interchanably, as there is no functional difference between the two. A Dual core system is literally a Dual CPU system with both cores on one piece of silicon instead of two.

So, if I had a 3.0 GHz Pentium 4, and a dual-core 2.8 GHz Pentium 4, the dual-core would smoke the single core, right?

No. The 3.0 would win, given today's codebase. Why, you ask?

Well, it goes back to the third problem with dual-cpu systems, that problem being that you need something to take advantage of 2 CPUs before you should go spend your money on a dual-CPU system. Think of it this way, if dual-CPUs offered a substantial advantage in gaming, then why do almost all gamers have a single-CPU system?

The problem lies with the vast majority of compiled code. Dual CPU, and therefore, dual-core systems will need a vast amount of multithreaded code that can be run in parallel. Think of "threads" as "atoms" of CPU code, pieces of code that cannot be broken down into smaller pieces and must be executed in sequence. A CPU can execute one thread of code at a time. Therefore, with two CPUs and dual core, one can execute two threads at the same time, provided you have more than one thread in the first place!
Most code today is notoriously single-threaded [serial] instead of being multithreaded [parallel]. This is why, if you're playing TFC, Hyper Threading from Intel doesn't give you a performance boost, because games are extremely serial and cannot be run effectively on two processors given current technology. This is not a problem of software developers, this is a problem with the compilers used to generate most of the finished code in use today. To properly utilize dual-core, compiler technology needs to revised to emphasize multithreading of applications.

AMD's dual core is really no more than two K8 cores right next to each other. Can't get much more simpler than that, really. AMD will release dual-core sometime in 2005 on the Opteron first [since multithreaded code is used mostly in the server sector], then on the Athlon 64 FX, and finally on the garden variety Athlon 64. It is unknown what the initial clock speeds on these CPUs will be upon release, however.

Intel's dual core dual core will be on a 90nm Prescott-based core called Smithfield. Each core will have 1 MB L2 cache, will run on 800 MHz FSB, and will support EM64T instructions. I do not personally know if EMT64 is compliant with AMD64/x86-64 instructions by now - I'd hope they would be. These chips will ship in Q3 of 2005, with the speeds as follows: x40 [3.2 GHz], x30 [3.0 GHz] and x20 [2.8 GHz].

Dual-core, for you early adopters, will probably start slower than regular single-cored CPUs, but they will prove their worth as more and more of the software industry optimizes their code to run on some flavor of a dual-CPU system.

[Direhit]

Q: I have two PC3200 memory modules that I know work perfectly fine individually, and at aggressive timings. However, when I try to use them together in the same board, I can only get the to work stably at PC2700 / DDR333 speeds. What's going on?

A: Certain memory controllers, whether they are built into the CPU itself (Socket 754 Athlon 64) or onto the motherboard, cannot use more than one double sided memory module at the same time, without forcing the user to underclock the memory.

The solutions to the problem:

1) Use one of your dual sided memory modules, and populate the other banks with single sided modules only. As for the other dual sided memory module, transfer it to another system.

2) Use only single sided modules (Crucial's PC3200 512 MB 8T-series, for example).

or

3) Run your system memory at DDR333 speeds, and live with it.

[Direhit]

Q: I found some memory that had a label that says "UTT" on the chips. Are these really the same Winbond BH-5 chips that were used in the previous generation premium memory modules?

A: The answer is somewhat complicated. While these chips can certainly perform the same as the BH-5 chips, the fact remains that UTT chips are untested, and are sold at Tier 2 prices to memory module manufacturers. These manufacturers in turn, then attempt to sell them as premium memory modules. The chips do NOT have the Winbond label on them, although they could very well be as good.

If the memory chips are OK, and if the epoxy and soldering used on the rest of the module is OK, then yes, you could very well have a premium memory module equivalent that rivals the old Mushkin "Black" memory from the last generation.

On the other hand, you're going to get burnt when buying these modules, since they are untested, and will have a higher defect rate than any quality controlled module. Furthermore, makers of such memory modules are looking to put forth a cheap module (in terms of their manufacturing cost), and will often times skimp when it comes to epoxy quality / printed circuit board quality, as well as soldering quality. Even if the chips are perfectly good, a failure in any of the other components can easily result in the failure of the entire module.

If you like to gamble, and don't mind running into a lot of lemons along the way, then buying such memory can certainly reap its rewards. Test the memory module thoroughly, with Memtest86, for at least 3 cycles. If the PCB, epoxy, and soldering are decent enough, then they should be able to handle the stress at the higher voltages, and not give you any errors after 3 cycles.

If you are running mission critical functions, don't use UTT memory. There's simply no sense in gambling when something this important is at stake. Go to an Indian reservation instead.