Voltage

[Strongwolf]

Been getting an 11.84 and 11.77 on the 12v Voltage reading. My psu is 700w ultra modular.
+3.3V--> 30A

+5V--> 34A

+12V 40A

Would that fluctuation be enought to unable SLI with 2 XFX8600GT?
Get BSOD with dual vc.

[Gizmo]

That's only 7 hundredths of a volt. If your system is THAT sensitive, then something is running on the ragged edge already.

However, it's worth noting that onboard mobo voltage sensors aren't worth squat. The have inaccurate voltage references that are subject to lots of drift, and the routing of signal traces means they are highly subject to noise.

If you want to know what your system is really doing, you should measure the voltage with a good meter, and if you really, REALLY want to know what your system is doing, you should look at the voltage rails with an oscilloscope. Your measuments should be taken using suitable common and voltage points at or near the item you are interested in (like the video card), as transients on the power bus may affect the voltage delivered to the DUT (device under test).

[Strongwolf]

An oscilloscope, ah? Well I think I pass on that one. You are right, the diference is very small and the readings not much thrusworthy. BSOD must be coming from another source. Thanks Giz!

[Áedán]

You can use a multimeter/voltmeter to get an approximation. However, that won't show you if there's very short term dips in the supply due to impedence along the way.

As for the motherboard monitoring chip, typically they have a resolution of 0.016 of a volt for voltages under 4.096V (as they use an 8bit ADC). That means they can only measure the voltage to the nearest 0.016V. However, 12V is over 4.096V so there's an external circuit that divides the voltage down.

This lowers the resolution of the monitoring chip, so the 0.07v difference you're seeing may be nothing more than the smallest voltage change the chip can determine. The real values could be 11.80 (which the chip might round to 11.77) and 11.81 (which the chip might round to 11.84).

[Strongwolf]

THK again, you are the best guys.

[Samuknow]

I would double check with a MM. You will notice that your 12v is a little on the low side. It is in spec but still low. How many drives are you running in that machine? Or 12 volt accessories for that fact.

[Strongwolf]

There are 2 WD 320 Gb Raid0 (I hope), 3 120mm fans (4 when close), 2x 8600GT (SLI), one DVD/CD/RW and FDD. This is W2.