Curious OC / Mem Problem?

I've been playing with this for days, and I cannot figure it out. I cannot break beyond a 250 / 5:4 clock.

P4P800 board
Processor 2.4C (tried various voltages all the way to 1.6)
Samsung DDR PC3200 (two 256MB sticks, running at 3-3-3-7, K4H560838E-TCCC)

I can OC the processor beyond 250, or the memory beyond 200, but not both at the same time?

I can run the processor to 275 in 3:2 mode

- or -

I can run the mem to 240 in 1:1 mode

I can run stable all the way to 250 in 5:4 mode (that gets me stock 200MHz memory), but if I try and go any further the system gets unstable.

So why can't I run 255 in 5:4 mode? That would give me memory of 204, which works great in 1:1 mode.

Any ideas?

Hehe, i have the same problem, my memory is kingmax pc3200, i can just about complete some sandra benchies before the system crashes at anything over 250mhz fsb, but the way i see it is....... I have a system that [email protected], every game runs smooth at max detail@ at least 1024x768 with fsaa, i have no problem

I know it doesn't help solve the problem, if i could overclock some more, i would. I have heard that many ddr400 modules do not overclock well at all, but i didn't want to pay the premium for ddr433+, oh well.

It does seem as though your only option is to change the CPU/mem clock multiplier, that would be setting it to 266mhz, that will give you the ability to overclock your cpu higher, but you'll reach a maximum of about 332/333mhz ddr, which would you rather loose? To be honest, i haven't tried to see how high i can go for a sustained period yet, but i'll try soon.

try giveng the ram voltage of 2.85

Hmmm. I tried disabling PAT (MAM in Asus BIOS), and broke through 250MHz. Haven't had time to see stability, max speed, etc, but MAM definitely breaks through the barrier.

Since it's an 865, and Asus is "enablind" PAT functionality, I wonder if this could be the weak point of the P4P800 vs a real 875 board. Or could it be some timing related to the way my Samsung PC3200 memory interacts with PAT mode?

Gotta stop fiddling for the evening. Will try some more tricks in a few days.

BTW - I tried 2.85, to no better.


Does anyone have definitions for:

DRAM Idle Timer and DRAM Refresh Mode? Are there things I can be trying with these two settings?

And what the heck does "Turbo" do?

Well I tried upping the memory voltage, I hadn't tried that before, quite strange, nethertheless myt situation has not changed, although it was nice to see the dragothic 3dm2k1 test running at over 400fps, when it crashed i was no longer amused.

I'll stick to 250mhz fsb for now, seems stable enough.

The Turbo/standard modes just increase the memory timings i think, i always have mine on turbo, apart from last night when i was fiddling around.