Pushing the Corsair 750TX to the limit?

[volks1470]

So i'm very curious to how much power my 750TX can put out. I've read a couple reviews saying it's capable at 900W draw.

System specs as of now.

Phenom II 965 @ 3.9GHz
MSI 790FX-GD70
5870

Now I curious to find out if the PSU can handle the 2 extra 5870s I have coming in the mail.
I know it doesn't have enough PCI-E connectors but that can be remedied by using the molex/PCI-E connector perhaps?

This site says the a trifire setup plus a i7 980X @ 3.471GHz only used 641W running Stalker: Call of Pripyat

http://translate.googleusercontent.com/translate_c?hl=en&ie=UTF-8&sl=auto&tl=en&u=http://www.hardware.info/nl-NL/articles/amdnampoZGCa/Clash_of_the_Titans_3way_SLI_GTX_480_test/15&prev=_t&rurl=translate.google.com&twu=1&usg=ALkJrhggjzLwVoPRT15k2SY8r6n2xpBuGw

 

[Lmeow]

Well, two HD 5870s in CFX, with an i7 975 3.33GHz, uses around 600W of power. I'd say that three of them with a Phenom II X4 965 o/c to 3.9GHz would take around 750W - 800W. IIRC, 900W draw means that the PSU draws 900W from the wall, which, at 80% efficiency, is less than 750W, although I could be wrong.

Considering that you are overclocking as well as having three HD 5870s in CFX, go for a Corair TX950W or HX850W - because remember, a PSU at full load too often will stress out the components and has a higher chance of failing early, as well as the incredibly loud fan noise which occurs during 90%+ load on Corsair PSUs.

 

[soundefx]

I think that you will be very close the max of the PSU, which is never a good thing, no matter how good the PSU is.

 

[XMSYellowbeard]

I would not suggest putting 3x of those cards on this PSU and especially not with an OCed system.

 

[Raidur]

Yeah id start with 2 and invest in at least a 850w with a GPU setup like that. I think you'd be stable for a while though on what you have, but I wouldn't do it.

 

[shovenose]

forget wattage.
howe many amps does each card need? multiply that by 3, then see how much is on the 12volt rail.
it is not good to run a psu at more than 85% or so capacity continuosly for a long time. it being a corsair, it may be able to do it for a while.

 

[xxenergyxx]

Oh interesting question.

But, I would like to ask you, what kinds of tools did you utilize to over clock your 965? what kind of cooler? As you can see, I have the same CPU

 

[XD_dued]

So you can spend 1200 dollars for graphics and not $120 on a PSU?

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139009

I'd say go with that or greater so you don't risk damaging anything.

I guess another question is...what resolution are you running at and do you really need 3? XXDD. I can get 35-40fps on my 5850 OC on crysis maxed out at 1920x1200

 

[shovenose]

heres what i recommend, just so you dont run the psu at full load and so you have a little head room if you want a few additional hard drives or something.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139013
as XD_dued said, if you spend so much on gfx cards then you MUST have 150 bucks for what some say is the most crucial piece in your copmuter. of course, without a psu, your system wouldnt work. also, the psu determines the longevity of your compnenets and the stability of your system. lousy psus have even blow up and take your $1000 graphcis cards/mobo/ram/cpu/hdd and everythign else with them when they die!!!!!!!!!!!!!!!!!!!!!!!

get it?

 

[XD_dued]

Wow btw this is a good price on the egg:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139013

EDIT: lol @ shovenose you beat me to it.

 

[shovenose]

lol yeah i firgured that was a good price. but i would never spend more than $30 on a used generic china crap psu HAHAHA

 

[jsc]

A 5870 needs about 12 amps or so per card. Figure about 12 amps for an OC'd CPU. Figure another 4 - 5 amps for a couple of hard drives, an optical, and fans. Figure another 80 watts of 3.3 and 5 volt power for logic and memory.

You're up around 700 watts or more than 90% of rated capacity.

Just because Corsairs can operate well past their ratings doesn't mean you should.

 

[volks1470]

A 5870 needs about 12 amps or so per card. Figure about 12 amps for an OC'd CPU. Figure another 4 - 5 amps for a couple of hard drives, an optical, and fans. Figure another 80 watts of 3.3 and 5 volt power for logic and memory.

You're up around 700 watts or more than 90% of rated capacity.

Just because Corsairs can operate well past their ratings doesn't mean you should.

PSU ratings
+3.3V@30A
+5V@28A
+12V@60A
-12V@0.8A
+5VSB@3.0A

Not sure about those assumptions but heres some of my numbers

each card consumes 188W which should be 15.6A. Three cards would be 47A. The PSU is rated to handle 60A.

I have no idea what the PII965 consumes OC'd, so lets say put it at stock clocks, 125W. So correct me if i'm wrong but wouldn't the CPU consume 10.4A. Which rail does the CPU run off of?

Add in all other peripherals ~8A.

I have some numbers of Amperes but I'm not sure what rails they run on. Anyone want to help? And remember, the OC'd 6 core 980X and 3 5870s only pulled 641W during gaming.

*This setup isn't long term* i'm selling one of the 5870s because it doesn't support voltage control. I just want to throw that third one in there just to see what kind of benchmark numbers can be pulled off.

 

[jsc]

Short term, I think you would be OK. You can pull 66 amps and still stay in specs:
http://www.hardwaresecrets.com/article/505/8

 

[FALC0N]

Since you (the original poster) already have a corsair 750, I would use it. Corsairs are extremely stout. And they will are always UNDERRATED not overrated.

That hardware secrets review linked above is a good example as they are one of the best for PSU's. From the review:

......can (it) really deliver its rated 750 W at 50º C. Not only that. During our tests we could pull up to 900 W at 45º C. So you will be basically buying a 900 W power supply paying the price of a 750 W one. What is sweeter than that?....

Like I said, Corsair is as good as it gets.

Now if you were looking for a new PSU from the beginning I would say yes, go a little bigger. But no point in paying another $120 when you already have a fine unit that is up to the task.

 

[FALC0N]

A 5870 needs about 12 amps or so per card. Figure about 12 amps for an OC'd CPU. Figure another 4 - 5 amps for a couple of hard drives, an optical, and fans. Figure another 80 watts of 3.3 and 5 volt power for logic and memory.

You're up around 700 watts or more than 90% of rated capacity.

Just because Corsairs can operate well past their ratings doesn't mean you should.

I agree in general with your math, but you miss the point of WHY quality PSU's like corsair perform beyond their rated specs. It is in part so you CAN run them at their rated specs without risk of pushing them too hard. If Corsair says 750 watts, they mean it will handle sustained 750 watts.

 

[FALC0N]

Could also take a little of the guessing game out of it by buying something like kill-a- watt for $20 and see how much it really draws once together. Besides, kill-a-watt is fun to play with. If you do, remember that the draw at the outlet is about 10-15% higher than the PSU output.

 

[volks1470]

So you can spend 1200 dollars for graphics and not $120 on a PSU?

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139009

I'd say go with that or greater so you don't risk damaging anything.

I guess another question is...what resolution are you running at and do you really need 3? XXDD. I can get 35-40fps on my 5850 OC on crysis maxed out at 1920x1200

Well at 5760x1080 games really slow down. I want to be able to still apply some anti-aliasing too.