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I have a Gigabyte P55M-UD4 board with an i7 860 and 4GB G.SKILL Ripjaws DDR3 1600 9-9-9-24 memory. I've overclocked it to 3.6GHz with BCLK of 200MHz, CPU mult of 18x, and around 1.21V. I've enabled all the various power saving features of the i7: C1E, Cx state, EIST, and left turbo boost and thermal threshold monitor to auto.
I've found that my "bottleneck" is the RAM. It defaults to 1333MHz, and trying to use XMP defaulted it to 2000MHz, which is evidently beyond its capability. I manually set the memory mult to 8x so that its overall frequency is 1600MHz.
This worked fine for the most part, but I still get the occasional glitches that might be due to overclocking (I can't tell). I'm not sure if it's the CPU overclock's fault or the memory overclock, or maybe something else. The CPU was roughly stable at 1.2V, and I've been incrementing it up to 1.225V with no apparent change. So that leads me to believe the instability is being caused by the RAM.
Now here's the odd part. I've read that I'm supposed to leave memory "Performance Enhance" (which I believe affects tRD) to "Standard" at least for pre-P55 chipsets. Right now, I'm using XMP and a Performance Enhance level of "Turbo". The odd thing is that when I set Performance Enhance to Standard, it refused to boot! I tried disabling XMP and it still wouldn't boot. It would only accept a level of Standard if I reduced the frequency back down to 1333MHz or less.
I set Performance Enhance back to Turbo to get it to boot again (leaving frequency at 1600MHz), but I'm now back to square one, which is that the system is still slightly unstable (I think).
Any suggestions? I don't want to increase the voltage that much, since I have a SFF build which has less cooling potential (though I do have decent cooling in the form of the Corsair H50). In the meantime, I'm going to try increasing memory voltage to 1.56V and see where that gets me...
Thanks.
I've found that my "bottleneck" is the RAM. It defaults to 1333MHz, and trying to use XMP defaulted it to 2000MHz, which is evidently beyond its capability. I manually set the memory mult to 8x so that its overall frequency is 1600MHz.
This worked fine for the most part, but I still get the occasional glitches that might be due to overclocking (I can't tell). I'm not sure if it's the CPU overclock's fault or the memory overclock, or maybe something else. The CPU was roughly stable at 1.2V, and I've been incrementing it up to 1.225V with no apparent change. So that leads me to believe the instability is being caused by the RAM.
Now here's the odd part. I've read that I'm supposed to leave memory "Performance Enhance" (which I believe affects tRD) to "Standard" at least for pre-P55 chipsets. Right now, I'm using XMP and a Performance Enhance level of "Turbo". The odd thing is that when I set Performance Enhance to Standard, it refused to boot! I tried disabling XMP and it still wouldn't boot. It would only accept a level of Standard if I reduced the frequency back down to 1333MHz or less.
I set Performance Enhance back to Turbo to get it to boot again (leaving frequency at 1600MHz), but I'm now back to square one, which is that the system is still slightly unstable (I think).
Any suggestions? I don't want to increase the voltage that much, since I have a SFF build which has less cooling potential (though I do have decent cooling in the form of the Corsair H50). In the meantime, I'm going to try increasing memory voltage to 1.56V and see where that gets me...
Thanks.