Vista Windows Experience Index RAM dilema

[rjb]

Foxconn K8S755A-6EKRS Socket 754 http://www.newegg.com/product/product.asp?item=N82E16813186069
AMD Athlon 64 Processor 3400+ 2.4GHz
2 x 512MB Corsair Value Select http://www.newegg.com/Product/Product.asp?Item=N82E16820145026
1 x 1024MB Corsair Value Select http://www.newegg.com/product/product.asp?item=N82E16820145505
NVIDIA GeForce 6800
37GB Raptor SATA
120GB Maxtor PATA
Windows Vista Ultimate

I installed Vista on this system and the Windows Experience Index rates it a 2.3 based on the RAM memory operations per second. The Processor is 4.2, Graphics 5.9, Gaming 5.9, and Primary Hard Disk 5.2. If I take OUT the 1 gig stick the RAM subscore shoots up to 4.0. If I take out 1 512MB and leave in the 1 gig and 512MB it scores 4.2. It seems the system does not like all three sticks for some reason.
All 3 sticks are good. I had them in a different PC. Windows and the BIOS see all 2GB of RAM. It is just that the WEI rates it so low and it bugs me. I tried moving the RAM to different positions in the slots with no luck. Any suggestions?

 

[LintMan]

I presume you have the 512MB pair in the same memory channel? If you didn't and also had the 1GB stick in tossed there, that might slow down your timings.

Maybe you could try downloading some memory benchmarks and running them with your different configs. That would tell you if this was some quirk in Vista's Experience Index rating, or if your actual performance is varying.

 

[Matthias99]

I was going to say that it's probably the loss of dual-channel -- but it's a S754 system, so it's single-channel both ways.

Is it going down to DDR333 or something with all three DIMMs installed? Also, the 1GB DIMM is rated CL3, and the 512MB ones are CL2.5 -- that should be a pretty minor difference, though. Try CPU-Z and see what it says your memory timings and speed are both ways.

You can also try the memory benchmarks in a program like SiSoft Sandra (assuming they have a Vista version, or that the WinXP one works).