question about running 4 sticks of ram

Hi!

I currently have 1GB of 3200XL Xtra Low latency Cas2 400MHz ram (2x512).

i am about to buy a new system which also takes ddr ram, the new system has 4 slots for ram.

if i run my current 3200XL ram in the dual channel slots, and then buy another 2 sticks of corsair ram (TWINX-3200C2, 2x512) which is also cas2 and 400MHz (but doesn't have the "Xtra Low Latency" sticker.. wahtever that means), will this be ok?

i assume the 3200XL stuff will be running in dual, and the other two sticks wont be.. will the fact that the "other" two sticks are NOT the same as the dual pair be a problem? i'm hoping not because they are the same speed and have the same CAS..

TIA.

You cannot have some of the memory running in dual-channel mode and some of it not. Dual-channel is a property of having two physical memory controllers, each controlling one memory channel.

If you could get the modules to work (often mis-matched memory will not run on a system, Athlon 64 systems are rather sensitive to this), then it would most likely be by relaxing the latencies (I.E. CAS 2.5, etc) and increasing the voltage.

If it was an A64 system, then they would also run a 2T command rate which puts a rather large dent in your memory bandwidth. This is a memory controller limitation! Another consideration is that many A64 systems will force you to run 4 modules at DDR333 where 2 modules could run DDR400.

The best bet for 2 GB of memory on a new system is to run 2 * 1 GB rather than four modules.

You CAN run 4 modules, it is definately possible, but often tricky.

Memtest86+ is your friend.

PLUR

CK

thanks for the reply!

i suppose this means that i'll have to spend $400 instead of $200. :(

what a bummer.

ps it is going to be an A64 system, good guess :)

You can always eBay the existing modules or use them for a Christmas present!

Yes, it's a pain, but the Athlon 64 memory controllers still have some big limitations. I've seen word of the latest revision San Diego cores having a newer controller that had more flexibility, but I think you'd still be reduced to a 2T command rate and since the modules aren't matched, you could still encounter issues there.

FYI, Newegg.com has TwinX2048-3200C2's on sale right now for $240 with a $25 mail in rebate. HERE.

PLUR

CK