GTX275 SLI on a Corsair TX650 v2?

[Guest]

Could I run a second GTX275 on my Corsair TX650 v2 power supply?

specs,

i7 3770
Asrock z77 Extreme6
Kingston HyperX 3K SSD
Seagate Barracuda 1TB, 64MB Cache
2x4GB 1600MHz Corsair Vengeance LP DDR3
XFX GTX275

 

[Mousemonkey]

I wouldn't advise it.

 

[Guest]

Thanks, I'll just stick the better cooled one in and sell the other

 

[hitesh12]

A single gtx 280 needs a 600watt power supply .
So same here , not advisable.

 

[bucknutty]

The GTX275 has a max power draw of 219watts. Figure 2 would have a max draw of 440. That leaves 210 watts for the cpu board and drives. That would be close but would probably work.

I could not find any specs on the needed amperage, but I am guessing each card could draw around 30 amps. Chances are that PSU cannot do that, and you will end up with lots of instabilities.

If you have some documentation that states the PSU is good for 60+ amps I would try it.

 

[hitesh12]

@bucknutty - Minimum 550watt required
http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-275/specifications

 

[bucknutty]

@bucknutty - Minimum 550watt required
http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-275/specifications

The website gives a recomendation for total system power not for the GPU alone. By that math 2 video card would need a 1100watt psu? Thats not right. That video card has a max draw of 220. In reality it only draws around 180.

http://www.tomshardware.com/reviews/geforce-gtx-275,2266-14.html
here we see a gtx275 and entire computer only pulling 251 from the wall under max load.

Again the wattage is not the issue, its the amperage. Many 500-600 watt PSUs can only put out 30 or 45 amps. That will not be enough and will cause instability.

 

[hitesh12]

Well what I meant was that adding another gtx 275 in that left 100watt would not be a good idea.
And never said that 1100watt for 2 gcs.

btw I misread the first line of your first post. Thought you meant that 210 watt is left for the graphic card. My bad.

 

[Guest]

12V rail is 53A, which means 636W on the 12V rail alone.

@Bucknutty: I don't understand what you mean when you say it is not the wattage but the current? V*I=W

 

[Guest]

Unless you mean that cheaper power supplies do not deliver the advertised wattage to the 12V rail

 

[bucknutty]

12V rail is 53A, which means 636W on the 12V rail alone.

@Bucknutty: I don't understand what you mean when you say it is not the wattage but the current? V*I=W

Maybe that was not the best way to experess my thought.

Although the math based on the advertised wattage says the amperage should be x many times the PSU is rated at far lower. You could simply assume that 650/12=54.16 amps. but that may not be true because the PSU may use cheap parts, or the arrangment of 12v vs 5v vs 3.3v may make the usable wattage of the PSU much lower than advertised.

I did not look it up the PSU in question when I made my first statement. I was hoping the OP would.

The math suggests that each video card 220/12=18.3 so both video cards should be 37 total.
I7 is 77w part so lets say 77/12=6.5
We are now at 44, not including the board ram fans and drives which should be tiny in comparison. Lets say 6 amps to make the math easy.
We are now at 50.

This math suggests it might work. Lets look at newegg say and see what the PSU Specs are.
3.3V@25A, +5V@25A, +12V@53A, -12V@0.8A, +5VSB@3.0A
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020

Its close but it should work.

Here is a PSU that is advertised as 680 but the amperage ratting is very low.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817148022
+3.3V@38A, +5V@40A, +12V1@22A, +12V2@24A, -5V@0.3A, -12V@0.8A, +5VSB@2A
The math here suggests the PSU only has 552 watts on the 12v rail, Much lower than the advertised wattage of 680.

I guess I should have said looking at the advertised wattage is not issue to be concerned with. You should look at the actual wattage and amperage.

In conlusion I think this system will run fine. Some one check my math...and my logic... it has been a long and confusing day.

 

[Guest]

The TX650 is manufactured by Seasonic iirc.

http://hothardware.com/articleimages/Item1296/power.png

Test System Used in that chart

Core i7 920 (2.66GHz)

Gigabyte GA-EX58-Extreme
(X58 Express Chipset)

6GB OCZ DDR3-1066 C7
(3 X 2GB)

Integrated Audio
Integrated Network

Western Digital "Raptor" 150GB
(10,000RPM - SATA)

Just going off that chart alone says that a good 650W power supply could handle it, giving it 317W breathing room on the 12V rail (If that power measurement was purely from the 12V rail) to run a second GTX275.

Going on your calculations which are based on TDPs from Intel and Nvidia and the components running at 100%;

6.4166666666666666666666666666667A
18.25A
18.25A
=42.916666666666666666666666666667A so just say 42.917A

53-42.917 leaves 10.083A for mobo, ram, etc which means 120.996W for them, I don't think they'll consume anything near that so theoretically it should be fine, but in the real world component tolerances will make that number different.

So it looks like I'll put the second card in and hope the over-current protection kicks in if it is too much irl though it shouldn't need to.