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650W Seasonic PSU okay for Crossfire 6970's? - Page 2

post #11 of 52
Quote:
Originally Posted by ComradeNF View Post

So basically I might have some random shut-offs during benching? I really would not want that. Also, Jonnyguru listed that the efficiency was 88-90%, so at 90% load on the PSU I would expect that it would randomly shut off or something along the lines of that.
Now I'm starting to get worried. Problem is that there is a sale on this PSU for $100, and the 750W is $50 more, that's why I want this one.

Why would you see "random shutoffs"... I don't follow your train of thought.. what does efficiency have to do with anything?
post #12 of 52
Thread Starter 
Quote:
Originally Posted by Unoriginal Sin View Post

Why would you see "random shutoffs"... I don't follow your train of thought.. what does efficiency have to do with anything?

I'm assuming if the cards try to pull more than 650W the PC will turn off or something like that. Isn't that how it works? I'm not too sure, I haven't ever had a PSU that just barely met the requirements.
post #13 of 52
Power supplies are rated at output and not input... so a 650W unit should be able to continuously output 650W(that's why you should always avoid stuff from Diablotek/Apevia/etc which are falsely rated)... efficiency only refers to the AC-DC conversion loss... eg. a 650W unit which offers 90% efficiency at full load, will draw 722W from the outlet to deliver 650W(650/0.9).. while a 650W unit returning 80% efficiency at full load will draw 812W from the wall to deliver the same 650W(650/0.8).

Shutoffs on quality unit happen when various protections kick in, in your case most likely OPP at around 750W(where it's set for your particular unit) so you won't see any shutoffs due to load.
post #14 of 52
Thread Starter 
Wow, thanks for that. I haven't taken physics in years so I forgot all of that nice stuff. +Rep!

So the unit will push 650W no matter what then? That's a relief. So then I am guessing I should have no issues at all with 2x 6970's with my CPU while using that PSU?
post #15 of 52
YW!.. and no, you won't have any issues.. you can even get some reasonable overclocks for the cards(~1.1v) and you'll still be ok... the CPU is a non issue independent of clocks.
post #16 of 52
Quote:
Originally Posted by ComradeNF View Post

So then I am guessing I should have no issues at all with 2x 6970's with my CPU while using that PSU?
It depends.

At stock a CF of 6970 should account for 370-380W DC when gaming, up to 450WDC when stress testing (FurMark, OCCT and the like).
Add (I'm making and educated guess) 100-120W DC on load for the rest of the systems (I have noreliable figures for stress testing).

So, at most you should draw at least 570W DC (up to 500W DC when gaming): which are Seasonic's load voltages, temps and efficiency at - say - 570W (or 500W) DC on 650W?
I think you can perform some checks on those data using JonnyGuru and SPCR reviews, for example.

As OC'ing would add some more watt at those figures, 80W MIGHT be a small margin to deal with, but this latter is just my very personal opinion about.

Please take also note that the Corsair AX-650 should be sort of a clone of the Seasonic X-650/X-660 (AFAIK it's based on the very same platform).
post #17 of 52
Quote:
Originally Posted by Unoriginal Sin View Post

YW!.. and no, you won't have any issues.. you can even get some reasonable overclocks for the cards(~1.1v) and you'll still be ok... the CPU is a non issue independent of clocks.

1.1v is undervolting..? The stock voltage for 6970s is 1.175, unless you are referring to something else? Youll be fine OP, I have both my 6950s at 6970 clocks and my 955 overvolted as well as the other normal stuff (case fans, 2 hard drives, watercooling pump) and my system only draws 600 watts from the wall (thats the highest ive ever seen it, even when benching or with vsync off playing dirt 3.) On my TX650 from corsair. Like someone else said, if it was a lesser brand I would be worried, but seasonic is like the best of the best thumb.gif
POLARIS
(14 items)
 
Red Alert SR-1
(14 items)
 
 
CPUMotherboardGraphicsRAM
Intel 3570k 4.5Ghz 1.25v AsRock z77E-ITX XFX Reference 2GB 6950 1015/1500 1.255v 8gb Gskill Trident X 2400 C10 
Hard DriveCoolingOSMonitor
Samsung 830 128GB Ek Supreme HF White Acetal/EK FC 6970 Windows 7 Dell U2913WM 2560x1080 
PowerCaseMouseAudio
Cooler Master Silent Pro Hybrid 1050w Caselabs Mercury S3 Logitech G500 Fiio E10k USB DAC 
Audio
Creative Aurvana Live! 
CPUMotherboardGraphicsRAM
Phenom II 955 BE (4.4Ghz @1.52v) NB @ 2870 Gigabyte 990FXA-UD3 Rev. 1.1 [F4] Dual Reference XFX 2GB 6950s (950/1437) 1.25v 8GB Gskill DDR3 1333 CL7 @1412 
Hard DriveCoolingOSMonitor
Vertex II 60GB, 2x Caviar Black EK Supreme HF, EK FC 6970 Windows 7 Ultimate Alienware AW2210 1080p 
KeyboardPowerCaseMouse
Logitech Illuminated Corsair 650TX Cooler Master Storm Scout Logitech G9 
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POLARIS
(14 items)
 
Red Alert SR-1
(14 items)
 
 
CPUMotherboardGraphicsRAM
Intel 3570k 4.5Ghz 1.25v AsRock z77E-ITX XFX Reference 2GB 6950 1015/1500 1.255v 8gb Gskill Trident X 2400 C10 
Hard DriveCoolingOSMonitor
Samsung 830 128GB Ek Supreme HF White Acetal/EK FC 6970 Windows 7 Dell U2913WM 2560x1080 
PowerCaseMouseAudio
Cooler Master Silent Pro Hybrid 1050w Caselabs Mercury S3 Logitech G500 Fiio E10k USB DAC 
Audio
Creative Aurvana Live! 
CPUMotherboardGraphicsRAM
Phenom II 955 BE (4.4Ghz @1.52v) NB @ 2870 Gigabyte 990FXA-UD3 Rev. 1.1 [F4] Dual Reference XFX 2GB 6950s (950/1437) 1.25v 8GB Gskill DDR3 1333 CL7 @1412 
Hard DriveCoolingOSMonitor
Vertex II 60GB, 2x Caviar Black EK Supreme HF, EK FC 6970 Windows 7 Ultimate Alienware AW2210 1080p 
KeyboardPowerCaseMouse
Logitech Illuminated Corsair 650TX Cooler Master Storm Scout Logitech G9 
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post #18 of 52
You're probably referring to custom designs(factory overclocked cards maybe?).. 1.175 is not the typical voltage for reference 6970s smile.gif
Also... Seasonic is a top manufacturer.. but best of the best it is not wink.gif
post #19 of 52
Quote:
Originally Posted by Unoriginal Sin View Post

but best of the best it is not wink.gif
Quite an important statement, which need some supporting reasoning (IMO).
post #20 of 52
Quote:
Originally Posted by Unoriginal Sin View Post

You're probably referring to custom designs(factory overclocked cards maybe?).. 1.175 is not the typical voltage for reference 6970s smile.gif
Also... Seasonic is a top manufacturer.. but best of the best it is not wink.gif

Coulda swore the default was 1.1v for 6950s and 1.175v for reference 6970s. My reference 6950 was at 1.1, I know that. Cant prove you wrong for the stock volts on a 6970 though... tongue.gif

Also, who would you say the best manufacturer is? They make PSUs for half the brands out there, they must be PRETTY good. They always seem to get high reviews from the guru. Please prove me wrong, I would like to learn something today biggrin.gif
Edited by Shadow_Foxx - 3/13/12 at 2:54pm
POLARIS
(14 items)
 
Red Alert SR-1
(14 items)
 
 
CPUMotherboardGraphicsRAM
Intel 3570k 4.5Ghz 1.25v AsRock z77E-ITX XFX Reference 2GB 6950 1015/1500 1.255v 8gb Gskill Trident X 2400 C10 
Hard DriveCoolingOSMonitor
Samsung 830 128GB Ek Supreme HF White Acetal/EK FC 6970 Windows 7 Dell U2913WM 2560x1080 
PowerCaseMouseAudio
Cooler Master Silent Pro Hybrid 1050w Caselabs Mercury S3 Logitech G500 Fiio E10k USB DAC 
Audio
Creative Aurvana Live! 
CPUMotherboardGraphicsRAM
Phenom II 955 BE (4.4Ghz @1.52v) NB @ 2870 Gigabyte 990FXA-UD3 Rev. 1.1 [F4] Dual Reference XFX 2GB 6950s (950/1437) 1.25v 8GB Gskill DDR3 1333 CL7 @1412 
Hard DriveCoolingOSMonitor
Vertex II 60GB, 2x Caviar Black EK Supreme HF, EK FC 6970 Windows 7 Ultimate Alienware AW2210 1080p 
KeyboardPowerCaseMouse
Logitech Illuminated Corsair 650TX Cooler Master Storm Scout Logitech G9 
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Reply
POLARIS
(14 items)
 
Red Alert SR-1
(14 items)
 
 
CPUMotherboardGraphicsRAM
Intel 3570k 4.5Ghz 1.25v AsRock z77E-ITX XFX Reference 2GB 6950 1015/1500 1.255v 8gb Gskill Trident X 2400 C10 
Hard DriveCoolingOSMonitor
Samsung 830 128GB Ek Supreme HF White Acetal/EK FC 6970 Windows 7 Dell U2913WM 2560x1080 
PowerCaseMouseAudio
Cooler Master Silent Pro Hybrid 1050w Caselabs Mercury S3 Logitech G500 Fiio E10k USB DAC 
Audio
Creative Aurvana Live! 
CPUMotherboardGraphicsRAM
Phenom II 955 BE (4.4Ghz @1.52v) NB @ 2870 Gigabyte 990FXA-UD3 Rev. 1.1 [F4] Dual Reference XFX 2GB 6950s (950/1437) 1.25v 8GB Gskill DDR3 1333 CL7 @1412 
Hard DriveCoolingOSMonitor
Vertex II 60GB, 2x Caviar Black EK Supreme HF, EK FC 6970 Windows 7 Ultimate Alienware AW2210 1080p 
KeyboardPowerCaseMouse
Logitech Illuminated Corsair 650TX Cooler Master Storm Scout Logitech G9 
  hide details  
Reply
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