Abnormal Power Usage

[trefaes]

I've moved this question to a new thread since I figured it wasn't anything to do with the thread I originally posted it in.

In the last few months of having used my old, decrepit computer which has been having stability problems for ages (30-50% CPU usage taken up by DPCs for some reason), our power usage almost doubled although at the time, we couldn't figure out the cause of the increase.

The PC went poof on Christmas Day after a power surge, the hard drive and fans spin up but there's no display, even after trying a different graphics card and monitor, so I'm guessing it's the motherboard.
Now I'm no longer using it, our power usage has returned to normal... so unless it's some major coincidence, I'm guessing it definitely was the computer.

What I'm wondering is, can a PC actually draw a lot more power than it actually needs? And if so, what would cause it to do so?

It's specs are
Intel P4 2.66GHz
ATI Radeon 9600 Pro
Antec True 330W PSU

 

[Corasik]

Your PSU is rated at 330W, so if it draws much more than that, it would pouf the PSU.

Assuming that PSU is 70% efficient, it would be drawing around 470W at full load. So its maximum draw would be around 11 units (kwH) per day. Assuming it was left on 24/7

How much power are you trying to account for?

However, an ATi 9600 doesnt use that much power unless I am much mistaken, and while the CPU at 30-50% uses more power than CPU idle (P4's use HLT state when idle which reduces power consumption), A 2.66Ghz P4 at full load would still only draw around 80-90W. If it was overclocked then anywhere up to 120W, much more than that and it would overheat and throttle back anyway.

For reference, my Core 2 Duo (2.66Ghz) system uses 120W Idle, and around 170W with both processor cores loaded to 100%. While gaming it varies from around 160W to around 225W depending on the game. (GPU is Geforce 7900GTO)