I7, ex58-ds4 voltage problem, please help


May 4, 2009
CPU: i7 920, CO stepping, cooler thermalright ultra 120 EX i7
MB: ex58-ds4
RAM: 6GB corsair 1600 c9d

I'm currently running the CPU @ 3.33MHz (166x20), Vcore 1.248V in CPUZ, eventhough i set 1.3V in BIOS. Its tested stable, 63 degree C load (under P95), also my Ram is running at 1333MHz with 8-8-8-20 timing, command rate 1T, voltage 1.64V

The problem I got is that when I tried to increase CPU speed over 166, I would have to increase voltage so much to be able to boot the system.

At 183MHz (3.66). Vcore: 1.46V to boot to Windows but crashed after 2 sec of Prime 95. I then increase Vcore up to 1.51V and it crashed after 10 min in prime 95, temperature was at 70 degree C at this speed

At 175MHz (3.5). Vcore: 1.41V to stablize system (only 3hrs Prime95 though)

Is there any potention problem with my CPU/MB?, because everyone else seems to be able to get the CPU running at 3.8GHz with Vcore of 1.35 or something.

Whenever I set Vcore in BIOS, the amount shown in CPUZ or speedfan is always .05 lower (eg: 1.3 in BIOS, 1.25 in CPUZ...), is this common ?

I can't seem to get it stable at 3.8GHz, and is it worth it if Vcore would have to be so much (like 1.45V+)?

Is my ram timing good, can I improve anything else at my current speed 3.33GHz?


Jun 22, 2009
I just finished overclocking on a gigabyte extreme, 920...

I woudn't put u'r vcore up to 1.51 again, infact i'd keep it around 1.40 or so...i have the same problem where voltage set in bios appears/is lower on cpu-z. I'm thinking cpu-z is the more accurate reading. Ideally u want to stay under 1.375 volts on vcore, so 1.40 should be max. I'm at 4ghz at 1.38 something volts (in bios) and 1.36 on cpuz (d0 step - if that matters).

u might be getting crashes/errors because your memory or uncore is not set right.

what is u'r uncore speed? should be twice your memory, so at least 2666mhz.
whats QPI/VTT voltage? set it around 1.3 or something.

Maybe put your dram voltage to 1.66 if its not. Gigabyte defaulted to 1.5v volts on my memory (at lower speeds) but the memory behaved erratic at that voltage.