Undervoltin 920 in RIIE

axsnetworks · Post by **axsnetworks** » Sat Mar 27, 2010 12:48 pm

Hello everyone
I'm trying to under volt my CI7 920 D0, and I can get it stable at 1.05v, the thing is that I have it installed in a Rampage II Extreme, which allows setting the voltage, no problem there... the issue is that when the speed step kicks in (drops the speed to 1660 from the 2.66 original) the voltage does not drop to the 0.94v default, but stays at 1.05... has anyone else experienced this issue???
any insight is welcomed, as I plan on water cooling this CPU and a 5870...
thanks in advance

axsnetworks · Post by **axsnetworks** » Tue Mar 30, 2010 3:28 am

Update....
I was able to lower the Voltage to 0.925, and this gives me better temps than the speed step enabled...
the only question I have is, why does hwmonitor show I'm consuming more current at lower voltage...????
thanks in advance

b_rubenstein · Post by **b_rubenstein** » Tue Mar 30, 2010 4:01 am

The first question to ask about all instrument readings is does it makes sense? If there is lower voltage than their should be a lower power draw. (W = V x I) If the power calculation is the same or higher with the lower voltage AND the CPU frequency is the same, the the current reading in HW Monitor is off.

axsnetworks · Post by **axsnetworks** » Tue Mar 30, 2010 4:28 am

Yeah that where my question comes into play....
if P= V*I then that's where I ask... is the motherboard asking for more amps to compensate for the lower voltage???
I'm kind of curious how does the HWMonitor find out the Power usage....

b_rubenstein · Post by **b_rubenstein** » Tue Mar 30, 2010 7:27 am

For a given voltage, it can only draw more current if it runs at a higher frequency or does more work. From Ohm's Law (I = V/R) I goes down if the voltage goes down.