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Is a Corsair TX850M power supply enough to run 3 7970s? - Page 7

post #61 of 62
Quote:
Originally Posted by TwoCables View Post

Not really, unless your average power draw is about that high.

On PSU Efficiency

PSU "50% Load" Myth

More: http://www.overclock.net/t/715889/psu-articles

Like I said "if you need 850W" wink.gif

From my own experience / system that I build around 9 months ago the sales guy warned me that 850W might not be enough for my rig but I was thinking "your just trying to scam me for a bigger PSU". I'm starting to think he was right because I've had two 850W PSUs die on me (TT Gold and XFX Gold from different stores) since then.

I've been wanting to get a 3rd 7970 in the next month or so and was planning on going a 1200W PSU, but I'm starting to think I'll go 1500W just to be sure.

My system:
Intel i7 3930K @ Stock
ASUS Rampage IV Formula X79
G.Skill Ripjaws Z F3-12800CL9Q-16GBZL 16GB DDR3
2 x Gigabyte 7970 3GB GHz Editions Crossfired
OCZ 120GB SSD (OS)
OCZ 240GB SSD (Games)
2 x WD 500GB HDD (Apps / Storage)
3 x Samsung 23" 3D 120Hz 5760 x 1080 Eyefinty
post #62 of 62
Quote:
Originally Posted by CoderX71 View Post


Like I said "if you need 850W" wink.gif

 

Many people would interpret that differently.

 

 

Quote:
Originally Posted by CoderX71 View Post


From my own experience / system that I build around 9 months ago the sales guy warned me that 850W might not be enough for my rig but I was thinking "your just trying to scam me for a bigger PSU". I'm starting to think he was right because I've had two 850W PSUs die on me (TT Gold and XFX Gold from different stores) since then.

I've been wanting to get a 3rd 7970 in the next month or so and was planning on going a 1200W PSU, but I'm starting to think I'll go 1500W just to be sure.

My system:
Intel i7 3930K @ Stock
ASUS Rampage IV Formula X79
G.Skill Ripjaws Z F3-12800CL9Q-16GBZL 16GB DDR3
2 x Gigabyte 7970 3GB GHz Editions Crossfired
OCZ 120GB SSD (OS)
OCZ 240GB SSD (Games)
2 x WD 500GB HDD (Apps / Storage)
3 x Samsung 23" 3D 120Hz 5760 x 1080 Eyefinty

 

A 650W PSU is enough for this:

 

http://www.guru3d.com/articles_pages/asus_radeon_hd_7970_crossfire_review,7.html

 

With two 7970s under full load in their system, their PSU pulled 567W from the wall outlet. Their CPU was idling, so I have to add up to 130W for a 3930K at stock. So with the 3930K at stock and under full load at the same time as the two 7970s, the PSU could pull up to 697W from the wall outlet. So if your PSU is 90% efficient while pulling 697W from the wall outlet, then your computer would be pulling 627W from the PSU. Your gaming power draw would be anywhere from 500 to 600W.

 

I don't know why those PSUs died, but it could be the outlet. Maybe it's bad and also not grounded. I don't know, but I know that a good 850W PSU is overkill for this.


Edited by TwoCables - 5/14/13 at 5:14pm
It's a computer!
(19 items)
 
  
CPUMotherboardGraphicsRAM
i5-2500K @ 4.5GHz (1.368-1.384V fixed voltage) ASUS P8P67 EVO B3 (UEFI ver. 1850) GTX 780 ASUS DirectCU II (1228 / 6300, 1.180V) G.SKILL Ripjaws X 8GB (2 x 4GB) 1866MHz, CL9 
Hard DriveHard DriveHard DriveOptical Drive
250 GB Samsung 840 EVO (C:\) 250 GB Samsung 840 EVO (D:\) 150 GB WD VelociRaptor Samsung SH-S243N 24x DVD Burner 
Optical DriveCoolingOSMonitor
Samsung SH-S203N 20X DVD Burner Thermaltake Frio Win 7 Home Premium x64 SP1 Retail AOC G2460PG (24" 1920 x 1080 144Hz G-SYNC) 
KeyboardPowerCaseMouse
Filco Majestouch 104-key Cherry MX Blues w/NKRO Corsair HX650 (Bronze, ordered on 12-12-2009) CM 690 Intellimouse Optical (1.1A) 1000Hz polling rate 
Mouse PadAudioAudio
Basic, but premium round X-Fi Titanium HD Klipsch ProMedia 2.1 (with 16 AWG Monster Cable... 
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It's a computer!
(19 items)
 
  
CPUMotherboardGraphicsRAM
i5-2500K @ 4.5GHz (1.368-1.384V fixed voltage) ASUS P8P67 EVO B3 (UEFI ver. 1850) GTX 780 ASUS DirectCU II (1228 / 6300, 1.180V) G.SKILL Ripjaws X 8GB (2 x 4GB) 1866MHz, CL9 
Hard DriveHard DriveHard DriveOptical Drive
250 GB Samsung 840 EVO (C:\) 250 GB Samsung 840 EVO (D:\) 150 GB WD VelociRaptor Samsung SH-S243N 24x DVD Burner 
Optical DriveCoolingOSMonitor
Samsung SH-S203N 20X DVD Burner Thermaltake Frio Win 7 Home Premium x64 SP1 Retail AOC G2460PG (24" 1920 x 1080 144Hz G-SYNC) 
KeyboardPowerCaseMouse
Filco Majestouch 104-key Cherry MX Blues w/NKRO Corsair HX650 (Bronze, ordered on 12-12-2009) CM 690 Intellimouse Optical (1.1A) 1000Hz polling rate 
Mouse PadAudioAudio
Basic, but premium round X-Fi Titanium HD Klipsch ProMedia 2.1 (with 16 AWG Monster Cable... 
  hide details  
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