6 amps running prime95

turbochris · 05-20-2004, 06:42 PM

I bench tested my setup today. It's a single board computer with an onboard LCD controller, a pentium 3 800, 256 megs pc133 , 20 gig 7200rpm hard drive, a teac notebook cd-rw, and a 12" LCD. I'm using a 250 watt AT power supply run off a 400 watt inverter.

The current draw was much lower than I thought it would be. The inverter pulled 4 amps at 12.4 volts when the rig was idle. i ran prime95 and when the cpu was loaded it pulled 6 amps at 12.2 volts. That means the whole rig only pulled 72 watts at full load!?!?!? 72 watts at the battery?!?!?!?!

could this be true?

PASware · 05-21-2004, 07:50 AM

thats low, but a p3 800mhz doesn't draw much "watts" (20.8watt) and your lcd wont draw more then 20watts orso, so it could be possible yeah

Rob Withey · 05-21-2004, 07:57 AM

Doesn't sound completely unreasonable. My P233MMX setup draws about 2.5A under load with a VFD.

turbochris · 05-21-2004, 04:02 PM

I figured stepping the voltage up to AC and then back down to dc would have killed the effeciency.

Kermee · 05-21-2004, 05:30 PM

Efficiencies are heavily dependent on the brand of inverters and also what you are powering. I've seen some DC-AC inverters as low as 70% (no-namers and cheapies) which claim '90%' efficiency and some which work as advertised near 93%-95% efficiency. With inverters, you do get what you pay for.