400W GPU on a 300W PSU

speedyink

speedyink

VIP Member
My friend bought a new video card for his computer, and is having me put it in. The card is a BFG 7800 GS OC 256mb, and it requires a 400W PSU. I noticed as I was putting in the card that his PSU only outputs 300W. I installed it anyway and tried it out, and it booted up fine. He is going to buy a 450W PSU soon, but until then is it safe to run the card in there anyway?
 
computermaineack said:
It should be fine, the card should downgrade itself to run at 300W.
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It cant "downgrade" it self, if it doesnt have enough power it will just simply not run and restart the computer of give you a black screen.

It should be fine if he's planning on getting a new PSU, just dont do any gaming with it yet.
 
What I would do for the time being is not plug in the power for the video card, the card will then automatically detect the lack of power connection and handicap itself accordingly. I did this with my NVidia 6600GT and I haven't seen any problems with it yet and I ran it that way for about 8 months, had the card almost a year. All in all, the unplugged cord should prevent the card from overloading the PSU, and then leaving him without a computer all together... :)
 
I think there was a guy who had some game...stronghold I think it was, and his GPU did the same. Then he upgraded his PSU, and it un-handicapped. I could be getting confused, but I'm pretty sure yours will handicap itself as well.
 
It'll either fail to boot, or crash durring intense loads. Be careful, leave it unplugged, and run light loads until the new PSU comes in. I had a 350w load on a 250w PSU for several months up until I got my new Thermaltake (see sig), and it was completely fine, but I don't have that much to loose. If it goes from overload, it may take the card, along with some of the system with it.
 
Keep in mind that there's a lot more to a PSU than wattage. A high quality 300W PSU would be better than a cheap 400W. If your PSU is overloaded, it may either fail to provide enough power during heavy loading (e.g. heavy gaming), or blow completely. DCIScouts' idea is a good one, and i'd avoid intensive gaming until he gets that new PSU.
 
DCIScouts said:
What I would do for the time being is not plug in the power for the video card, the card will then automatically detect the lack of power connection and handicap itself accordingly. I did this with my NVidia 6600GT and I haven't seen any problems with it yet and I ran it that way for about 8 months, had the card almost a year. All in all, the unplugged cord should prevent the card from overloading the PSU, and then leaving him without a computer all together... :)
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I already tried to unplug the cord, but the computer would constantly beep as soon as I turned on the power, and nothing would display on the screen. I am going to tell him not to game, but I think he's getting the PSU in a couple days or so, so it should be fine. I decided to test the card out with a short oblivion test, and it ran fine at high settings, though I'm sure I wasn't seeing the full potential of the card, since I saw similar performance to my card.
 
ceewi1 said:
Keep in mind that there's a lot more to a PSU than wattage. A high quality 300W PSU would be better than a cheap 400W. If your PSU is overloaded, it may either fail to provide enough power during heavy loading (e.g. heavy gaming), or blow completely. DCIScouts' idea is a good one, and i'd avoid intensive gaming until he gets that new PSU.
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Yea, with that there's also the stability of the rails, and the amperage.
 
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