I have a Thermaltake Toughpower 850w PSU. I am going to get a GTX 280 (which has a TDP of 236 watts) when it comes out along with all the supporting components. If i were to get a second GTX 280 down the road, would the 850w PSU be able to handle it? I will only use one HDD, core 2 q9450, 4 or 8 gigs of ddr2, all on a evga 750/780/790i mobo. Thanks

Nope, low quality PSU and low wattage. Get a 1kw PSU for safe measures.

List of good ones from best to least good:
-Enermax Galaxy S DXX 1000w (best)
-PC Power and Cooling Turbo-cool 1000w
-Corsair 1000hx
-Silverstone ST1000

Impossible to know until we see some definitive reviews.

toughpower is not a low quality psu by any stretch of the imagination... 850w will be cutting it close though, especially if you oc. you'd need close to 500w for the video cards with an oc and a heavy load, and at least another 200w for the rest of the components, you want to run a psu at around 50-60% load for best efficiency and less strain on the psu. 1kw would be your minimum.

Don't listen to Blood Raven.. the Toughpower PS's are great quality, and 850w will most likely be plenty with just your other components.

A normal system (no o.c. and weak/no video card) can get by on 200w of power. Raise to 300 for a good system, and 250*2 for the video cards.. and you come out with 800 total watts.. And im being fairly liberal with those figures.. You'll be fine with what you have

A PCI-E 2.0 card can get 300W at most, assuming it has a 6-pin and an 8-pin connector. At worst, your two cards will get 600W. With a quad CPU and the MB and the HDD, it's awfully close to the 850W limit. I think your PSU will do the job, but it will be very close to max. That will lower its efficiency and lifetime and it will increase the noise and heat.

I suggest you buy one card for now, and then do more research. Buy a new PSU together with the second card, if a new PSU is really needed. It's really hard to tell now. For example those cards may consume only 200W, not 300W, we don't know yet.

OK, I got a few more numbers for you. The GTX 280 will have 240 stream processors, and will use the same technology as the 9800GX2 (which has 128*2). This means the power requirements of the GTX 280 should be similar to those of the 9800GX2, maybe a bit lower - it depends on clocks.

PSUs certified for two 9800GX2 cards include the Toughpower 1000W but not the 850W.
The list is here.
http://www.slizone.com/object/slizone_build_psu.html

I hate to reenerate others, but aren't most thermaltake PSU's on the "80 plus" list?

I have a thermaltake toughpower cable management myself and every single thermaltake review i've read pointed to them being excellent PSUs

That's because stupid people listen to power supply marketing. As far as running your power supply at a high load, why not, you paid for that capacity, use it up.

why use two of these cards to run high AA at a millionxkagillion resolution at 60fps.

by the way things are sounding about the new Gtx 2x0's it look like they going to be fricken awesome, and i think it would be a little overkill to buy two of those giants....unless you just need to waste more of your endless supply of money on something......you know...whatever tho...just my 2 cents...

your PSU should be able to hold up with that load, but since you have the $$$ for 2 x GTX 280's then you shouldnt have issues any way - wait for reviews and see.

PS. if an AcBell 400 can handle a high end system with a 8800GTS (640mb) then im sure yours will handle the 280's

80 certified doesn't mean its a good PSU, just means it pulls less power from the wall, and so helps with the electric bill. Thermaltake power supplies in general are not the greatest, and the 850w has been known to have stability issues even more pressing than the rest of the toughpower series. Do some research, do not tell me I'm wrong because you bought a Thermaltake power supply, I hate that. The Thermaltake power supplies usually get the job down, however, but the problem is that his system would run damn close to 750-800w which is dangerous to even a great PSU. aevm is absolutely right though, those figures could change drastically soon but by the information you presented, then no that PSU will not work, sorry.

It might, there are power supplyies that can deliver over 100 percent load, not many though, and I would not want to. Plus if you oc your gonna draw a LOT of power, lots more than stock by at least half again I bet...it all depends on a lot of variables and we better wait for the reviews or it's just guessing.

I would venture to say a PP&C 860 watt will do the job. A 1Kw powersupply is really a waste in all but the most demanding systems. If you run a 1Kw but only use 700ish watts, your actually wasting alot of money just on your electric bill.

The PC P&C is actually certified for two 9800GX2 cards, which in fact contain more stream processors than two GTX 280s, so yeah, I believe you're right there.

Your other statement though is completely wrong. A system that needs 700W and runs on a 700W PSU will cost you MORE than the same system running on a 1000W PSU, all things being equal. For example a 700W PSU that normally reaches 85% efficiency at its best will work at less than 80%, maybe as low as 70%, when pushed close to 700W. A 1000W that normally reaches 85% efficiency at its best will work at about 85% when pushed to 700W. With the 700W PSU you consume 700W*100/70 = 1000W from the wall (assuming 70% efficiency at the end of the supported range), while with the 1000W PSU you consume 700W*100/85=823W . That is, the 1000W PSU SAVES you 177W on your bill, while the 700W PSU makes you pay for it, and even worse, it turns it into heat inside your case.

Look, the power rating of a PSU is not the amount it uses from the wall. It is the MAXIMUM amount that it should be allowed to draw. Ideally you should aim for a PSU that is used at 50% to 75% of its maximum, to get the maximum efficiency of the PSU and minimize bills and heat. How much your system needs depends on GPU and CPU and disks, not on the PSU size.