Power Supply Crisis....

[lynx]

The digital multimeter should be most accurate, assuming it is calibrated correctly.

The onboard chip only has an 8 bit A/D converter so it is only accurate to about 0.05v. Your digital multimeter will probably have a 12 bit converter which should be accurate (in that range) to about 0.005v.

Your bios reading of 12.26v is without any processor or graphics load, and considering the accuracy of the onboard chip it is equivalent to your digital multimeter. That could easily drop to the 12.21v shown by aida32 (it is only 1 bit down on the A/D converter). I would be very suspicious of readings which vary much from the bios figure when the system is not under load.

In any case, normal voltages will probably vary by about 0.1v in constant monitoring.

If there's a monitor specifically from the motherboard manufacturer that will usually be the most accurate, I use Asusprobe but I find that Aida32 agrees exactly with Asusprobe,

[clocker]

Thanks.

[Shiranai_Baka]

After a full nights sleep, I come back on my computer only to find that it can't boot up to windows because of a windows corrupted file.... So.. I'll post when my computer is working again.

[harrycary]

Ahem, you should be looking into how many watts your components require and not the voltage requirements.

That is fundamental.

/my 2 cents.

[zapjb]

clocker  Posted on 8 May 2004 - 09:34
... Assuming that your PSU is not a complete POS then 400w should be plenty to run your system.

Too big of an assumption for me. Coughs ... Antec ... Now they're all going to think you're crazy. Shhh

[Shiranai_Baka]

I heard that some power supplies don't actually supply the 400W that it says it does.. is this true? is this relevant to what efficiency is?

[lynx]

The problem is that poor quality PSU's may be able to deliver their promised power, but stability suffers at the top end, so you may see unacceptable voltage fluctuations and dropoffs.

Remember too that although the total power capability may be 400W, there are restrictions on the amount of power you can draw on the different voltages. So you may have plenty of spare capacity on 3.3V and 5V, but be over the limit on 12V. If that is the case you would need a PSU with more capacity on the 12V circuits.

That's just an example, I don't know whether the 5900 uses the 5v line or the 12v line, it is unlikely to use both. That's the reason why Nvidia recommend a 480W PSU for the 6800 Ultra card, not that it needs all that much more power but because it is taking it all from one source so the others are beefed up (by the PSU makers) as a natural consequence.