350 watts + 7800gtx

A

Autochthon

Limp Gawd
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I have a small 1380 Antec case - uATX. It comes with an 80% efficient. (supposedly) 350 watt Antec uATX Power Supply. I believe the power supply is rated up to 300 watts and 18 amps on the 12v line. My current arrangement draws ~120 watts under full maxed load. I'm considering exchanging my old 7800gtx into the system and disabling the IGC. Best I can tell a 7800gtx 256 draws less than 100 watts at full power. This suggests that the maximum potential draw on the system would be something around 200 watts. This exceeds the 50% power use number I generally try to use as a rule of thumb but theoretically should still work. Any opinions or experience that might give me some idea whether or not this is practical?

Heat may also become an issue as MB temps already run almost 45C under full load - even without a hot running gtx card. But I do have a a bit of extra cooling to help clear the air around the video card.

thank you
 
How heavy is the PSU?

If you're running it near it's rated wattage it'll get hot, and that heat needs to go somewhere. a good rule of thumb is to weigh the PSU if it's "damn heavy" then you'll probably be ok.

If it's paper light then I wouldn't risk it.
 
Nvidia recommends at least 22A on the 12V rail for the 7800GTX. Wouldn't chance it.
 
It's heavy for an uATX supply but quite small maybe half or less the depth of a standard supply. It is cooled by a temp controlled 120 mm fan.

Are you certain a 7800gtx 256 requires 22A? I've seen recommendations as high as 26A but that was for whole system not the card itself. That sounds awfully high. The numbers I saw said around 100 watts which should be around 8-9 amps. The sheets say 350 watt P.S. single and 500 watt SLI. I just checked and I had mis-remembered the amperage on the P.S.; It is 18 amps on each of "2" rails so 36 amps total but I assume still limited to 18 amps per harness. For some reason I'm having trouble finding specific amperage info thanks for the replies.
 
Yes, I apologize I was lazy and didn't double check the dual rails before posting. Yes, that appears to be the same supply; same model number and total wattage. I don't know why they list 22.2A on each rail mine lists 18A on the sticker.
 
Autochthon said:
Yes, I apologize I was lazy and didn't double check the dual rails before posting. Yes, that appears to be the same supply; same model number and total wattage. I don't know why they list 22.2A on each rail mine lists 18A on the sticker.
Click to expand...

Weird. Anyway, yeah, dual 12V rails with 18A on each will be fine for the 7800GTX.
 
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