Abit AN8 Ultra memory upgrade

[Cherry]

Hi there,

I would like to add some extra memory to my PC based on
MB Abit AN8 Ultra 939 ATX with
AMD Athlon 64 3200+ (2.01GHz) and
2x512 Mb kit DDR400 (G.SKILL PC3200 F1-3200PHU2-1GBZX 1024MB kit DDR400, CL 2,0-3-3-6 @ 2,65-2,85 V)

But I am a bit concerned about doing this, as I looked through some forums and found out that it might bring problems rather than benefits:
forum.abit-usa.com/archive/index.php/t-110400.html (sorry, the system does not allow me to add "http : / /" in front of the line)
The PC configuration discussed in the thread is very similar to my one.

I did not go so much into details, but what I’ve got it should be two memory modules of the same type and size in DIMM1+DIMM2 and in DIMM3+DIMM4 to run it in dual channel mode that supposes to be much cooler than having an odd number of the modules.

It looks like the guy had problems installing an extra memory on this type of mobo. He found out that the extra pair should be not only of the same type and size like the first pair; it should be also from the same manufacturer! And even in this case, when all 4 slots are occupied, you’ll need to down-speed your DDR400 to 333MHz.

So, my question is: would the memory upgrade be worth the time/money input?

And if so, should I search for 2x512 Mb of the same type/manufacturer, or it could be a pair of another size/type/manufacturer?

Thanks in advance for your suggestions.

[Tetras]

Using 4 modules in a socket 939 system is a complex proposition that as you have discovered, has many potential issues.

First off performance, 4 sticks mean you must run at 2T command rate (regardless of processor core) and that will result in a slight performance hit.

You may or may not also have to run at 333 Mhz if your processor is an earlier Clawhammer or Newcastle core (later cores, such as Venice are unaffected) due to a memory controller limitation (note that many motherboards will automatically default to 333 Mhz even if your processor core is able to handle 4 at 400 Mhz). Running memory at 333 Mhz is a more significant performance hit than 2T command and should be avoided.

The last performance issue is dual channel mode, running mismatched (in size among a dual channel pair) or odd number of sticks results in single channel and that again is a performance hit greater than running in 2T. If you were to run in single channel, at 333 Mhz and 2T you may well notice a performance drop in CPU heavy and more recent games but in general usage (Windows, multi-tasking) you should still see a performance boost from 2GB (over 1GB).

Compatibility wise the motherboard is (generally) not the problem, what is, is the finicky memory controller on the Athlon 64. Later revisions improve memory compatibility but you may still have problems even with 4 sticks of the same model, from the same manufacturer.

Memory is not all made equal, the chips used vary and may not be the same several months down the line. While Intel systems are usually forgiving the built-in memory controller on the Athlon 64 is notoriously picky about mismatched memory. Dual channel kits are not a marketing ploy nor just for convenience, they are "optimal" from a compatibility POV because they are guaranteed to be identical (or if not identical, they should still work together).

The actual model isn't important other than it is unlikely to be the same and if you pair slower RAM with faster RAM it will all run at the speed of the slowest but for compatibility sake I would either get a new 512MBx2 matched pair from the same manufacturer (and the same model) or (and this is preferable) sell the 2x512MB and get a 2GB (2x1GB) kit (that way you are not going to have any problems).

[Cherry]

Thanks a lot for the detailed reply.

As soon as I am ready for the upgrade, I’ll most likely go for a 2x1GB kit.
And I can assure you this decision isn’t based on the possibility to have fun by selling my old 2x512MB, at least not solely

[Tetras]

The only snag is the price, 2GB (2x1GB) of DDR 400 is around £50, double the price of standard DDR2!

If you were planning on upgrading in the near future then I'd hold out but if the PC is gonna be with you for awhile, guess you'll have to pay the premium.

If you can sell the 2x512MB for decent money then that should at least eat some of the upgrade cost.

[Softix]

same here i only have 2gb ddr400 is pretty expensive wish i had money for a new motherboard

[Cherry]

Yeah, that’s it: new motherboard requires a new CPU, new memory and so on… And I bet there is no way to get the stuff for free!