Slooow memory scores - Corsair 2400

[Homebrew]

Im stumped on this one. System specs:
Asus p4b266c
NW 1.6 @133fsb (2.2)
2x256 Corsair XMS2400
WinXP

Sandra mem score - 2048/2061

Seems very low to me. Now I know Sandra isn't exactly the pinnacle of memory benchmarks but Im seeing
scores with similar setups around 3000.
Brother in law has exact same system and he is getting 3050 or so (same version of Sandra too).

I tried swapping out memory, and all bios tweaks. Of course its set to 2/2/2/5 there.

Any ideas?

 

[Duvie]

First of I am assuming you are only using the 1:1 ratio which with that fsb would only be 266mhz ddr or at pc2100 speed...I think the asus p4b266c only had 1:1 ratio at 133fsb anywyas....It doesn't matter what the memory says it is you are not running it at its rated speeds...At 2000 you are right at the range pc2100 memory runs at, period....looks right!!!

No pc2400 speed memory and I mean memory running at 300mhz ddr is doing 3000 in sandra...And i mean no system....You are mistaken at your friends or brothers system...pc3200 at 400mhz will be right at 3000 and there is no way you can achieve that with a 133fsb on an asus p4b266c mobo...no way!!!

 

[Homebrew]

Thanks for the info.

His Sandra scores are indeed above 3000, I saw them myself. Something is obviously
screwed up there..told him to re-install and try again but for some reason he is reluctant to do that

 

[Egrimm]

Your scores seem right for pc2100/133Mhz. Get about the same with my setup when I run those speeds.
To get about 3000 you need to run pc3200 speeds, the number description of the ram is the theoretical bandwith of the ram run at it's default speed (2100=133Mhz, 3200=200Mhz). I get the same as your brother when I run my Corsair PC3200 at 2/2/2/6 (200Mhz)

 

[AdamK47]

If he's getting 3050 then I can guarantee that his motherboard is different than yours. He's most likely using one based on the i845 which would allow running the memory at 3:4 when above 133MHz. On a 150MHz bus a 3:4 divisor would allow the memory to run at 200MHz (DDR400). Thats what I'm running at now and I get the same scores between 3000 and 3050.

 

[Egrimm]

Originally posted by: AdamK47 - 3DS
If he's getting 3050 then I can guarantee that his motherboard is different than yours. He's most likely using one based on the i845 which would allow running the memory at 3:4 when above 133MHz. On a 150MHz bus a 3:4 divisor would allow the memory to run at 200MHz (DDR400). Thats what I'm running at now and I get the same scores between 3000 and 3050.

There's also a 3/4 hack for the P4b266 series so you can run the memory assynchroneus when above 133fsb. Not all I845E boards have this option btw.
So if he has oc'ed his cpu too that could be the reason for the good memoryscores too

 

[Homebrew]

Idiot mode = true

Sorry ppl, he upgraded last week and neglected to tell me even though I asked about the p4b266. Just a misunderstanding.

Anyway, he is running a Albatron PX845PEV and traded the 2x256 Corsair 2400 for 1x512 XMS 3200. Really likes the Albatron so looking
into upgrading to that soon. $95 @ newegg..wow.

I tried the 3:4 hack for the P4b266 but since the memory runs at 2.5/3/3/7 (despite BIOS settings) over 290DDR that kind of defeats the purpose
of running a higher fsb from a memory standpoint. I would rather have 2/2/2/6 @ 140fsb.

Thanks for the help.

 

[Egrimm]

Originally posted by: Homebrew
Idiot mode = true
I tried the 3:4 hack for the P4b266 but since the memory runs at 2.5/3/3/7 (despite BIOS settings) over 290DDR that kind of defeats the purpose
of running a higher fsb from a memory standpoint. I would rather have 2/2/2/6 @ 140fsb.

Cas-setting has an influence but not THAT much. When running ddr400 cas 2/2/2/6 I get about 3030/2998 in Sandra, at cas 2.5/3/3/7 I get 2964/2960.. So yes, there's a significant difference but nothing as great as what you said, you would get 2100 or so with 140Mhz.

 

[AdamK47]

Originally posted by: Egrimm

Originally posted by: Homebrew
Idiot mode = true
I tried the 3:4 hack for the P4b266 but since the memory runs at 2.5/3/3/7 (despite BIOS settings) over 290DDR that kind of defeats the purpose
of running a higher fsb from a memory standpoint. I would rather have 2/2/2/6 @ 140fsb.

Cas-setting has an influence but not THAT much. When running ddr400 cas 2/2/2/6 I get about 3030/2998 in Sandra, at cas 2.5/3/3/7 I get 2964/2960.. S0 yes, there's a significant difference but nothing as great as what you said, you would get 2100 or so with 140Mhz.

That?s true. Unlike other motherboards, the CAS, RAS and CAS to RAS timings on an i845E don't have as big effect of an affect as clock speed does. On a 150MHz bus with a 1:1 divisor and 2-2-2-5 timings I get around 2300 in SiSoft SANDRA. With a 3:4 divisor and 2.5-3-3-6 timings I can get around 3000.

Another thing to note about the i845E boards is that at DDR400 it's very hard to run two DIMMs. Opt for one 512 module.

 

[Homebrew]

Thanks for the advice.

Going to try 3:4 again and re-bench but your right, the 2x256 pc2400 is really going to hold me back. Too bad memory prices are on the rise otherwise
might consider 1x512 xms3200.