I used to run an E8400 in my P5Q, and I had it at 4.34 GHz (482 FSB), with no problems whatsoever. I didn't really have to tweak anything, just bump up the CPU voltage a little bit. VTT, PLL, Northbridge voltage, all these things were at or near default values.
I swapped out the E8400 for a Q9650, and now I am having a hell of a time getting the FSB above about 435 MHz. Prime95 Blend just dies within a minute if I increase the FSB further. I dropped the CPU multiplier to 6 so I could just focus on maxing out the FSB first, so rule out any CPU issues (insufficient voltage, cooling, etc). Things that don't help whatsoever:
-Swapping memory. 2 DIMMS, 4 DIMMS, doesn't matter how much memory I have installed or where I put it.
-VTT. Increasing this to 1.4V and beyond doesn't help a bit
-Northbridge voltage. Increasing this to 1.4V and beyond doesn't help a bit
-CPU PLL. 1.5V up to 1.56V, no difference
-Loosening memory timings. 5-5-5-15 to 6-6-6-18, no difference
-Clock Skew. Upped both NB and CPU clock skew to about 300ps, no difference
-All of the memory settings that claim to improve FSB overclocking (static read control etc), none of them made any difference
I scoured online for hours, and tried everything that people overclocking this CPU suggested, to no avail. I know my motherboard and memory can handle much higher FSB, since my E8400 rocked up to 480+ MHz FSB. Yet this Q9650 just hits a wall around 435 MHz.
Any ideas?
EDIT: My actual limit is 432 FSB. 431 is just fine, 432 fails Blend within minutes no matter what I set in the BIOS. I went ahead and bought a Gigabyte UD3P. If that board can't push the FSB to at least 450 MHz, nothing will.
EDIT2: Got the UD3P. Goodbye FSB issues!
I swapped out the E8400 for a Q9650, and now I am having a hell of a time getting the FSB above about 435 MHz. Prime95 Blend just dies within a minute if I increase the FSB further. I dropped the CPU multiplier to 6 so I could just focus on maxing out the FSB first, so rule out any CPU issues (insufficient voltage, cooling, etc). Things that don't help whatsoever:
-Swapping memory. 2 DIMMS, 4 DIMMS, doesn't matter how much memory I have installed or where I put it.
-VTT. Increasing this to 1.4V and beyond doesn't help a bit
-Northbridge voltage. Increasing this to 1.4V and beyond doesn't help a bit
-CPU PLL. 1.5V up to 1.56V, no difference
-Loosening memory timings. 5-5-5-15 to 6-6-6-18, no difference
-Clock Skew. Upped both NB and CPU clock skew to about 300ps, no difference
-All of the memory settings that claim to improve FSB overclocking (static read control etc), none of them made any difference
I scoured online for hours, and tried everything that people overclocking this CPU suggested, to no avail. I know my motherboard and memory can handle much higher FSB, since my E8400 rocked up to 480+ MHz FSB. Yet this Q9650 just hits a wall around 435 MHz.
Any ideas?
EDIT: My actual limit is 432 FSB. 431 is just fine, 432 fails Blend within minutes no matter what I set in the BIOS. I went ahead and bought a Gigabyte UD3P. If that board can't push the FSB to at least 450 MHz, nothing will.
EDIT2: Got the UD3P. Goodbye FSB issues!