Someone explain this to me

[dedgar]

To Gigabyte motherboards, GA-965P-S3 and a GA-965PDS3.
Three different cpu's, 2X Q6600 (a B0 and a G0) and an E6600.
It doesn't matter which board has which cpu and I can't get the mobo with the Q6600 to go over 375 bus speed. (9X375 is the best it will do)
Put the E6600 on that same mobo and it is now very easily clocked to a 400 bus speed. (8X400) And right now the E6600 is at 8X425.
Using the same memory, coolers, voltage settings, etc. I've run the voltages up and down. I've tried changing the memory settings. All to no avail. Made sure the BIOS is the latest on both mobo's. Temperatures are not an issue for either the cpu or nb.
Q6600 or E6600
GA-965P-S3 or DS3
Mushkin DDR2 800
CM Gemin II + two 120mm fans
And I did read about the bus 'hole' on the Q6600 and tried to skip right to 3600ghz with 9X400 and 8X450. Again, no go. I haven't gone over 1.5V for the cpu, yet. Temp's have been good so that may be what iI try next on the Q6600's.
Someone have an idea of anything I might be missing?

[Yellowhello]

I think the problem is that quads are harder to OC than dual-cores in general.

[Tech Geek Deluxe]

Did you reduce the multiplier of the Q to 8 and up the bus speed yet?

[Quakindude]

You may as well take the CPU voltage right up to 1.5V and see how far you get. Anything above about 3.2-3.3GHz and I see folks saying to right to max voltage. Max Voltage/temp for that G0 stepping CPU is now 1.5V/71*C.