2GB using 512MBx4 Memory Question

[dklingen]

I am very interested in upgrading my system from 1GB (512MBx2) to 2GB (512MBx4). However, I would like some feedback from anyone that may have done this.

Can you answer the following questions for me:
1. Do all four modules have to be EXACTLY the same (brand / timing)?
2. Will the DDR speed drop from 400MHz to 333MHz?
3. Will the CAS change higher then 2.5?
4. Will the memory now run at 2T instead of 1T?

Thanks!

My System:
A64 Winchester 3200 @ stock speeds
512MBx2 of Corsair XMS3200C2 @ 2.5,3,3,8 1T
Chaintech VNF4 Ultra VE
ATI X800XL @ stock speeds

 

[imported_Kensai]

1. Nope but you'll run at the lowest timings.
2. Yes, but you can overclock them back to 400MHz+
3. Depends on which sticks that you buy.
4. Yes they will, you cannot change it.

 

[dklingen]

Thanks for the quick and specific input.

I have read that the impact of 2T vs 1T is only 2% on performance. If that is the case then the memory buffer gain I get should out weigh the performance hit. Would you agree?

 

[mOeeOm]

Originally posted by: dklingen
Thanks for the quick and specific input.

I have read that the impact of 2T vs 1T is only 2% on performance. If that is the case then the memory buffer gain I get should out weigh the performance hit. Would you agree?

Yup.

 

[Hacp]

More like 0-5% if you look at the xbit labs article.....

Blah I shouldn't have said that as now I might be forced to search for it .


http://www.xbitlabs.com/articles/cpu/display/athlon64-e3-mem.html

 

[dklingen]

Hacp,

Thanks for the excellent link to the Xbitlabs article!

 

[Paludis]

yeah well I got 4 x 512MB and I can't overclock it to 400mhz.. it's stuck on 160mhz (333) even if I change it to 400 in the BIOS.

anyway I see a big improvement in games like BF2 and F.E.A.R. but still, it's annoying running at PC2700 when I bought PC3200

 

[Davegod]

I think it depends on the mobo wether theyll run at 400mhz, possibly requires a rev E proc aswell?

 

[superfly27]

What's the difference if he sells the 2x512 MB and buys 2x1 GB?

I ordered 512 MB for a new mobo because I want to replace it later with 2x1 GB CAS2 and just sell the 512 MB. That's OCZ Platinum that DOES run at CAS2 on AMD platforms. I read only AFTER ordering Corsair XMS CAS2 that it only runs at CAS2.5 on AMD platforms. Forturnately, shoprbc (Canada) was able to change my order before it was sent out. (Then I got greedy and asked them over this weekend if they can add more stuff to my order. Guess I'll find out on Monday.)

 

[orangat]

Very interesting. I was under the impression all the while that 2T command rate would totally murder performance. I was contemplating biting the bullet and getting 1G modules. If its just a couple % points, its not bad at all.

Any other comments about filling up 4 dimms on the Soltek k8tpro-939?

 

[orangat]

Dammit...I just remembered about the drop down to 333 with the old winchester cores...

 

[Davegod]

eh wait a min, does 2x1gb modules have the same 2T issue as 4x512mb?

 

[orangat]

No. 2x1Gb is only a maximum of 4 banks so you have no problems with command rate.

 

[dklingen]

I spoke to Chaintech and they said that I should be able to run DDR400 with a beta bios they sent me. I get the memory tomorrow and will let you know. I am SO SICK of the HDD access in BF2.

See ya!

 

[orangat]

dklingen, I heard there is a chance (not sure how likely) that the winchester could burn out running at 400 instead of 333.

 

[MobiusPizza]

Originally posted by: Davegod
I think it depends on the mobo wether theyll run at 400mhz, possibly requires a rev E proc aswell?

Nopes. Memory controller is on-die

It's Winchester's problem

 

[dklingen]

AnnihilatorX,

I read the article linked by Hacp above from XbitLabs. Here is the key excerpt:

"If you remember, older Athlon 64 processors based on 130nm cores didn?t support 4 double-sided DDR400 SDRAM modules working at 400MHz frequency at all and reduced their frequency to 333MHz automatically. The today?s processors based on 90nm cores offer us a few better solutions. The D core revision also known as Winchester allows using four double-sided DDR400 memory DIMMs if the Command Rate timing is set to 2T."

Anyhow, I should find out tomorrow if my memory arrives.

 

[dklingen]

OK,

I installed the two new DDR3200 modules, now I have 512MBx4. The bios defaulted to 333, but I changed it to 400. I also had to move to 2T. Which is a big deal for memory bandwidth (you lose about ~1GB/s from 5600MB/s to 4800MB/s). However, it does not appear to impact games at all (as far as I can tell). To support this I have provided benchmark details (pre/post - basicaly 1T vs 2T - all the other memory timings are the identical in the test):

Here are the 1T results
PCMark02: CPU-6512, Mem-9984, HDD-1118
3DMark01: 20618
3DMark03: 10342
3DMark05: 4946
Aquamark: 62.9
CS SourceTest: 121.74

Here are the 2T results
PCMark02: CPU-6517, Mem-9560, HDD-1230
3DMark01: 20342
3DMark03: 10305
3DMark05: 4949
Aquamark: 62.19
CS SourceTest: 119.75

The memory upgrade made a HUGE difference in BF2 (no more hitching, loading, or whatever you want to call it at the beginning of map loads) at least in the three 32 player maps I played. Fear was better, but still seems to need better optomization for fluidity.

Key point: Look at the 3DMark scores and particularly the CS score. The impact of 2T vs 1T seems to be very trivial. From the CS score it is 2 frames slower (big deal). In the FPS games (HL2, BF2, Far Cry, and the Fear Demo) I could not tell the FPS impact in games. Maybe it's a couple of fps but well worth eliminating any possible HD caching IMHO!!!

BTW in case you are wondering why I didn't go the 1GBx2 path, it is to expensive (min. of $273 for 3,4,4,8 1T). Over twice what I paid for 512x2 ($122.80).

 

[ShadowBlade]

Wheather it slows to DDR333 or not depends on your core. I beleive AMD fixed this issue with Venice and San Diego.

EDIT: Sorry, didnt see you specs. Yes, it will slow to DDR333. Same timings are usually best, otherwise all will lower to the lowest one. Same brand is not required.

 

[BespinReactorShaft]

Would I get this same 400MHz -> 333MHz drop with a P4 Prescott & Abit IS7 mobo?

I'm also considering a 2x512MB -> 4x512MB upgrade and this is new to me.