Ga-p35c-ds3r + 8500C5D

Well my mb revision is 1.x and i 've had 2 sticks CM2X1024-8500C5D at a total of 2 GB. These two would run at 5-5-5-15@1066@2.2 volt, despite the fact that they should run at 2.1 according to their specs.

Yesterday i bought TWIN2X2024-8500C5D, another 2GB total. The new ones run at 2.2 volts(at 5-5-5-15 by default), but thing is that when i go 4-up with 1066 my system is unstable and i have to go to 5-5-5-18@800@1.8(by cpu-z) | 1.9(in bios)

Any way that i return to 5-5-5-15@1066 with all 4gb?

In most situations no difference at all, in rare occasions a small difference (a few percent at most).

If you want to run at 1066 you could up the voltage of the memory controller hub by 0.1 or 0.2V. Try it at 5 5 5 18 too, does the trick sometimes and no speed difference to 15.

Basically i cant raise the memory voltage...at 1066 my mb sets vdimm at 2.26 which is already high enough...

Last night for ~10 hours i run memtest with all modules at 800 and i got no problems....so i guess 800 is stable.

What would be a way to see if 1066 can be possible ? GMCH overvoltage ?

THanks for your time folks

Edited: Gigabyte gave the answer to overvoltaged VDIMM at default, said that the MB gave the DIMM as much as they needed to run smoother.