How to Use TWO PSUs? (for GTX480 QUAD SLI)

[Baasha]

Guys,

How does one use 2 PSUs for "one" computer?

I am planning to get the QUAD SLI set up with GTX 480s and I have a PC Power & Cooling 1200W PSU right now.

I will get another one of those PSUs but there's only one ATX connector on my motherboard, the Asus P6T7 WS Supercomputer.

Any suggestions/advice?

 

[HOOfan 1]

You shouldn't need another PSU

Even if you did, you would be better off just getting a single Silverstone Strider 1500W...better PSU, and they don't even make the Turbo-Cool 1200W anymore


But there are Y splitters for the ATX cable that you can use

 

[Silenus]

If he overclocks everything he might! See the Quad 480 video linked in the video forum. 980X + Quad 480 SLI came in just under 1500 watts with everything OC'd.
http://www.youtube.com/watch?v=vY8uppkjwL0

 

[JAG87]

Even if you did, you would be better off just getting a single Silverstone Strider 1500W

Wow what bad advice...


If you need dual psu, you can use an adapter like these:
http://www.legitreviews.com/images/reviews/952/nzxt_khaos_019.jpg

It just brings the two power switching wires to the other PSU, so they can both be shorted when you press the power button.

Quad doesn't scale well at all, you will be putting out a huge amount of heat and using a ton of power for little in return. Unless you are doing this for benchmarking, stick to 3-way max and watercool.

 

[yh125d]

My suggestion/advice? Don't do it. Don't WASTE $2000+ on a space heater that plays games. I'm confident theres something else in life you could spend it on. Get two, maybe, if you're at 2560x1600, but keep the rest for something else.



And this is no slight against nvidia if anyone takes it that way, I wouldn't recommend 5870 quadfire either.

 

[Modelworks]

Be very careful how you connect power wires if you use two PSU. Connect the second supply to one or two video cards and nothing else in the system. You do not want the voltages from one supply connecting directly to the other one so don't mix supply connections on a single card either.

 

[HOOfan 1]

Wow what bad advice...

I might be wrong about not needing another PSU...but if he doesn't overclock all of the components...(why would you need to with such overkill) then I think the 1200W Turbo-Cool is still enough.

Other than that, my advice was not to buy another Turbo-Cool 1200W. They haven't made them in months, possibly over a year. If he buys one, it would be used, or certainly over $400. As I said, the Strider 1500W IS a better and more efficient PSU for that type of output. I said buy a single, because there is no need to have an exact match when running Dual PSUs.

Even using the video showing 1488 watts being used...what is the setup? That is power draw from the wall...not power draw from the components. Are they using 2 PSUs? That will make the system more inefficient. How efficient are the PSUs being used? I'd say they are pulling 1250W TOPS...probably not even that much...and that is with everything overclocked.

If he gets something like the Ultra X3 1600W, or the Silverstone Strider 1500W and tries them, they may very well work flawlessly. Very unlikley that he would be pulling that type of power for more than a few minutes even during gaming....benchmarks like the nVidia one used in that video are meant to stress the cards. If the X3 1600W or 1500W prove to be unstable, then get the ATX Y splitter and hook up your 1200W Turbo-Cool. Better yet, just get a smaller 600W unit that is independently regulated for the videocards.

Better yet, don't bother with something as extravagant, yet useless as quad GTX 480.

 

[JAG87]

I might be wrong about not needing another PSU...but if he doesn't overclock all of the components...(why would you need to with such overkill) then I think the 1200W Turbo-Cool is still enough.

Other than that, my advice was not to buy another Turbo-Cool 1200W. They haven't made them in months, possibly over a year. If he buys one, it would be used, or certainly over $400. As I said, the Strider 1500W IS a better and more efficient PSU for that type of output. I said buy a single, because there is no need to have an exact match when running Dual PSUs.

Even using the video showing 1488 watts being used...what is the setup? That is power draw from the wall...not power draw from the components. Are they using 2 PSUs? That will make the system more inefficient. How efficient are the PSUs being used? I'd say they are pulling 1250W TOPS...probably not even that much...and that is with everything overclocked.

If he gets something like the Ultra X3 1600W, or the Silverstone Strider 1500W and tries them, they may very well work flawlessly. Very unlikley that he would be pulling that type of power for more than a few minutes even during gaming....benchmarks like the nVidia one used in that video are meant to stress the cards. If the X3 1600W or 1500W prove to be unstable, then get the ATX Y splitter and hook up your 1200W Turbo-Cool. Better yet, just get a smaller 600W unit that is independently regulated for the videocards.

Better yet, don't bother with something as extravagant, yet useless as quad GTX 480.

I know the video is an extreme scenario but it's still a bad choice in my books.
Here, looks like you are spot on with your estimate:
http://www.hardware.info/nl-NL/articles/amdnampoZGSa/4way_SLI_GeForce_GTX_480_test/12

First, you are very close to the maximum capacity of the psu. Lets say you manage to pull 1400/1500w, you are pulling over 90% of the capacity. You generate more heat and you would be surprised how your efficiency goes down the drain. Two 1000w psus running at 75% capacity would be more efficient.

Point number two is that you are insanely close to the 15A cutoff point of north american outlets. I don't know where the OP lives (if it's 240V its a different ball game), but I sure wouldn't put that much load on one line.

Point three, your last sentence sums it up.

 

[HOOfan 1]

Yeah, I think the best advice is to forget quad SLi with the GTX 480...it is great for some benchmark sites who get them free, but for a consumer....useless. Even for folding...I can't imagine spending that kind of dough on folding.

 

[theAnimal]

Even using the video showing 1488 watts being used...what is the setup? That is power draw from the wall...not power draw from the components. Are they using 2 PSUs? That will make the system more inefficient. How efficient are the PSUs being used? I'd say they are pulling 1250W TOPS...probably not even that much...and that is with everything overclocked.

The system is using 2x Tagan BZ1300.

 

[bunnyfubbles]

I might be wrong about not needing another PSU...but if he doesn't overclock all of the components...(why would you need to with such overkill) then I think the 1200W Turbo-Cool is still enough.

You are wrong. Each GTX480 can easily pull ~240+W alone, thats nearly 1000W just for the GPUs.

Sure, you could probably get the system to power up, but you have very little breathing room at all. That much GPU power would be wasted without a heavily overclocked CPU.

 

[HOOfan 1]

You are wrong. Each GTX480 can easily pull ~240+W alone, thats nearly 1000W just for the GPUs.

Sure, you could probably get the system to power up, but you have very little breathing room at all. That much GPU power would be wasted without a heavily overclocked CPU.

Yes, I was wrong to say he shouldn't need another PSU

1000W for all the GPUs at max power draw...250W for everything else...I think that is realistic...I said 1250W max for everything. Either way, still no need for two 1200W PSUs.

a 1200W and a 600W, a 1200W and a 700W that should be enough. Of course assuming he has two separate circuits to plug them into.

It's still not a realistic system for consumers.

 

[v8envy]

Epeen builds are fine. It's just that most people doing them don't realize a practical, non-epeen system will equal the performance in 6 months and surpass it in 12. Or at least it did, back when we had GPU competition.

Back on topic. With mild overclocks each 480 could draw as much as 350 watts (PCIe specifies a max of 300 watts) running furmark or other "power virus app." Even non-overclocked they can hit 300W, and *will* considering how hot it's going to be with 4 of them even on an open bench. Computer hardware draws more power as it gets hotter.

That doesn't leave a lot of headroom for a CPU (presumably 125-130 watt), required extreme cooling, and misc. Shooting for around 2000 watts would be a safer bet for this kind of insanity. Don't forget to install 25 amp fuses and make sure your room cooling is up to the task of extracting an extra 2000 watts (the PSU will be dissipating a fair bit of heat at this load as well). If not, I could see your office turning into a sauna and the PC performance plummeting as the GPUs thermal throttle. Those bad boys operate at very close to their thermal limit, and raising room temperature even 20-30 degrees might push them over the edge.

If you're not sure get two 1200 watt space heaters, turn them on for 12 hours or so and see if your house wiring and A/C can keep up. Better yet, put the space heaters in the case you expect to house this in and see if temperatures inside it manage to stay within 30 degrees of ambient. The Fermi may be fine operating at boiling points of water, but the rest of your hardware is not designed for that kind of thermal stress.