Am I doing Prime95 wrong?

hterag

hterag

hterag

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7 Nov 2007
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Prime95 never gives me any errors, ever. At least not on my current system. I'm still fairly new to Intel overclocking; having been a long time AMD user, I know what Prime95 looks like when it finds a problem, it just isn't doing it.

I'm using a Maximus Formula, Q6600(G0) and OCZ 6400C4 ddr2.

Currently aiming for 3.4GHz and ideally 3.6GHz, hitting a wall at 3.2GHz.

FSB at 400mhz completely stable, 8x multiplier to get 3200MHz CPU.

FSB Termination: 1.44V
Vcore: 1.40V (CPU-Z says: 1.384V)
Northbridge: 1.63V

Temperatures never get above 62 degrees C according to Core Temp... Basically it's really good right now, stable and great. Motherboard is stable and cool, RAM is stable and cool, CPU is stable and cool.

But I cannot for the life of me get it any higher at all, surely with only 1.38v vcore I should be able to get higher? People have suggested disabling loadline callibration, but as soon as I do, it's no longer stable.

I mean it's not a case of "lol erroz", red icons all over the place, the machine just reboots. If I disable loadline callibration, the machine will reboot randomly, if I try increasing the FSB any higher or increase the multiplier to 9x it does the same. Within seconds of a Prime95 run it'll just reboot.

There's no inbetween, my other machine will reach it's limit and Prime95 will show it, it'll fail the self-tests etc. and stop the thread(s).

I've even tried whacking the voltage up to 1.5v just to try and get 3.3ghz but to no avail, it still just reboots without showing any errors. Is it the limit of the CPU? Is the motherboard not supplying a stable enough voltage?

I find it so hard to believe it'll go from rock solid stable at 3.2 to "ROFL bye" at 3.3, any suggestions greatly appreciated. If you need any other details I'll be happy to provide them.

Thanks in advance.

P.S. Yes, I have got round-off checking enabled. :P

EDIT: Wow, got carried away there, didn't realise how big this message is...
 
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RAM is running at 4-4-4-15 2T (stock is 4-4-4-15 1T but I don't trust it...) @ 2.16V(BIOS set to 2.1) The RAM is stable, I've memtest'd and prime large fft'd it for hours at that speed with the cpu at stock.

With a 9x multiplier I have to lower the FSB to ~355 but that's just the same final speed of 3.2GHz. I haven't actually tried pushing it that far with a 9x multiplier, the motherboard will easily get to 450MHz though but the CPU can't handle that at anything above 7x multiplier.

That's not the RAM I'm using though, I'm using this: https://www.overclockers.co.uk/showproduct.php?prodid=MY-090-OC

Thanks for the reply though.
 
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Short of upping voltages, try the following:

Max out your GTL ref clocks
disable transaction booster for max CPUZ (relax level 3)
Disable static read/write control
disable everything in the advanced CPU menu
enable loadline callibration
disable spread spectrums
Set ram to 2T


I agree about enabling loadline calibration. I have tested this on a few Maximus Formula SE bios' and the Maximus Extreme. The advice given about disabling it is just plain wrong!
 
Thanks for that weescott,

I've already got the transaction booster disabled (although at 0 relax level), disabled the static read/write control and everything in the advanced CPU menu. I haven't touched the spread spectrums setting, what does it do? And what about the GTL ref clocks? I haven't really fiddled with that either.

I've also got all the fluff (firewire, ide controller etc.) disabled too, if that helps. :S
 
Spread spectrum is something to do with EMI. GTL ref clocks are to do with voltage feed to the CPU.

I think your biggest hurdel is trying to clock with 1T enabled and tight timings. That on its own puts stress on the chipset/FSBT. Without those extra jiggawatts you would struggle.
 
Well I'm actually using 2T, the memory is rated for 1T apparently but as I said, I don't trust it and apparently my unjustified distrust has been justified.

Still, I'll keep at this, I'm determined to at the very least run 3Dmark06 once at 3.6GHz, even if I have to blow on the cooler myself!

Do you think if I loosened the timings to 5 5 5 15 it'd have any effect? I'd rather not cos I paid a £5 premium a few months back to get this memory! :P
 
Slacken the timings first to rule out the ram being the limiting factor in your oc. Then if all goes well tighten the timings 1 by 1.
 
Well, problem solved, this really is amazing...

The northbridge was running at around 50-52 degrees C. I've heard that's a bit warm already and decided it'd be worth trying some cooling on the northbridge.

The results are staggering, I've attached an Antec Tricool 120mm fan(one of the stock fans I replaced in my Antec Nine Hundred) to the side window and the temperature of the northbridge instantly dropped to 40-41 degrees C! I never expected such a tremendous drop, I've only heard of these sorts of temperatures on the SE (water cooled) version of this board.

To top it all, not only have I got it from 3.2GHz to 3.6GHz but I've even got it up to ***4.21GHz*** and it still boots, just, it's not stable (obviously, and silly hot), but at 3.6GHz it is.

Unfortunately the fan is STUPIDLY loud compared to the rest of my system so I'm looking into the highest CFM 120mm fan at 20dB or lower, this is a lot to ask but does anyone have any suggestions?
 
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