1:1 memtest stable, not prime stable

[GST-97]

OK, I have my 2.8E @ 3.5, running stable for weeks now on 1.42V, but it's only prime stable if I use 5:4 and run the memory at 200 Mhz (250FSB)

I have OCZ Gold PC3700 Rev2 RAM, and I can run memtest at 1:1 250 all I want and have no problems. But I boot into windows, get amazing sandra and aida32 benchmarks, but prime95 fails fairly quickly.

The only weakness that I know of in the system is the 350W power supply, but newegg just shipped my Sparkle 530W PSU and I should have it early this week.
I really don't see the PSU affecting this however.....

I have tried running at default timings to 3-4-4-8, prime will fail quickly... within a couple minutes.

I have the VDIMM at 2.9V, so it's getting plenty of power (gotta love that EVP)

Are there any other settings I should try? the GAT/PAT settings perhaps? they are all on auto.

I just find it odd that I can run memtest over and over and not have one single error, but prime will fail very quickly.....

Thanks for any help you may have...

-Chris

 

[Dark_templar]

For GAT setting put as follow Auto , Auto, Auto, Disable, Disable

c if it helps.

 

[scanido]

It might also be from your CPU. Are you certain your P4 is stable at 250FSB? If your uncertain you can always drop the mem ratio to 5:4 to test out.

 

[FIZZ3]

The RAM is less likely to be the bottleneck than the CPU is, according to your test results. You may want to try a bit more VCore, you have plenty of room from 1.42.

If you want to test the PSU issue, you could run the system as you have it now, but reduce the 12V load by physically disconnecting as many unnecessary devices as you can- think about optical drives and 'backup' disks.
If it tests better with the reduced load on the PSU, it is indeed a factor of importance to your overclock.

 

[KrisMCool]

While it sounds like more of a CPU issue, I recommend you lower your vdimm. I have the same memory and it doesn't like anything over 2.75v. I know it sounds odd, but mine is stable at FSB 250 with 2.75 vdimm and unstable with 2.85 vdimm. Just a suggestion. Your new PSU should eliminate power issues - Prescott is a hungry pig at higher vcores. Good luck.

 

[GST-97]

Yes, the processor is stable at 250 FSB, it runs prime95 just fine, no errors.

I will try those GAT settings when I get home tonight.

-Chris

 

[GST-97]

OK, just tried out some of the suggestions.

I put it to AAADD on the GAT settings, dropped timings to 3-4-4-8, prime95 errored within 1 minute of running.

Lowered Vdimm to 2.7, prime95 errored.
upped to 2.8, prime95 errored.

I went back to the bios, changed it back to 5:4, back to SPD defaults (2.5-3-3-6), and have been running prime95 for 10 mins now as I post this with no error yet.
Still at same 250 FSB, only difference is memory speed/timings.

While it was there, AIDA32 gave me 6336 MB/s read, 2140 MB/s write, sandra gave me 5854/5837

As I have said, I ran memtest for quite a few runs through and it gave no errors... maybe under processor load, there just isnt enough power... I will have to test again with new power supply when it gets here

Will let you know if anything works... and still open to suggestions

-Chris

 

[coughman]

Can your Vdimm go below 2.7V? I have the OCZ 3700 gold rev2 also and initially I had the same problem. The OCZ support guy recommended me to lower the Vdimm to 2.65V and prime95 has been happy since. good luck.

 

[GST-97]

Ya, my board will do 2.5, 2.55, 2.6, 2.7, 2.8, 2.9, 2.95 and I think .05 intervals up to 3.20V

I guess I can try 2.6V when I get home. Still doesnt explain why its memtest stable though. I would think if it didnt like the 2.9V I had it at, memtest would fail... maybe I'm wrong

New PSU should be here by Thursday

-Chris

 

[batboy]

Memtest just checks to make sure your RAM tests ok at the frequency, timings and ratio that you happen to have it set at. It is not a stress test at all. Just because the RAM checks out ok, don't mean the system is stable.