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PSU for Gtx 780Ti - maybe Sli?

post #1 of 22
Thread Starter 
Sup guys,
I waited so long for some benchmarks of the R9 290x and got disappointed. The price is quite nice here (480€ for the Msi R9 290x), but the power consumption and heat output are not great. So I decided for the msi gtx 780Ti, which costs 590€. I don't like the price, but it's the best single gpu right now.
However I thought about to go with two gtx 780Ti in Sli. I also thought about to go with a single 780Ti and when the 8xx comes out (soon? maybe this year?) to sell the 780Ti and buy two 8xx's.
Now my question; will my PSU be enough for two 780Ti's ? Sea Sonic X-Series X-660 660W ATX 2.3
I looked at benchmarks and all gtx 780 Ti in Sli used 550W-650W. My problem is, I read in forums "you need at least 750W, no you need 850w, no you need 1200i Platinum XYZ..." what now? How can a 7970 or R9 290(x) in CrossFire (each something like 300W) need a 850W psu, if the 780Ti also need a 850W psu (250w draw each 780ti) ? That makes no sense for me, because the Nvidia cards are not that power hungry. I used in the past two 560Ti's well OCed (each more than 200W) without a problem. Right now I have a 7970 Matrix OCed to the limit.
My specs:
Ram: G.Skill Sniper 2x8GB 1866
Motherboard: Asus Maximus VI Extreme
Cpu: i7 4770k 4,2ghz
Cooler: Corsair H80i
Gpu: 7970 Matrix
Psu: Sea Sonic X-Series X-660 660W + 80 Gold

Hope you can help me.
post #2 of 22
I'm no expert but I would say 650 watt is a little low. I have two 780 ti classifieds and my corsair 750 watt has problems (with over clocking) as those suckers can yank up to 400 watts a piece when your over volt. I will upgrading to a corsair 1000 watt shortly.

I would say if you're just running stock clocks you should be safe on 750-850 watts. But if you want to tweak volts at all I'd go for 850-1000 watts.

Also I can highly recommend a 780 ti sli setup, it scales great and is ideal 100 fps+ gameplay at 1440p ultra in everything but cry engine.
post #3 of 22
Quote:
Originally Posted by civerol View Post

Sup guys,
I waited so long for some benchmarks of the R9 290x and got disappointed. The price is quite nice here (480€ for the Msi R9 290x), but the power consumption and heat output are not great. So I decided for the msi gtx 780Ti, which costs 590€. I don't like the price, but it's the best single gpu right now.
However I thought about to go with two gtx 780Ti in Sli. I also thought about to go with a single 780Ti and when the 8xx comes out (soon? maybe this year?) to sell the 780Ti and buy two 8xx's.
Now my question; will my PSU be enough for two 780Ti's ? Sea Sonic X-Series X-660 660W ATX 2.3
I looked at benchmarks and all gtx 780 Ti in Sli used 550W-650W. My problem is, I read in forums "you need at least 750W, no you need 850w, no you need 1200i Platinum XYZ..." what now? How can a 7970 or R9 290(x) in CrossFire (each something like 300W) need a 850W psu, if the 780Ti also need a 850W psu (250w draw each 780ti) ? That makes no sense for me, because the Nvidia cards are not that power hungry. I used in the past two 560Ti's well OCed (each more than 200W) without a problem. Right now I have a 7970 Matrix OCed to the limit.
My specs:
Ram: G.Skill Sniper 2x8GB 1866
Motherboard: Asus Maximus VI Extreme
Cpu: i7 4770k 4,2ghz
Cooler: Corsair H80i
Gpu: 7970 Matrix
Psu: Sea Sonic X-Series X-660 660W + 80 Gold

Hope you can help me.

 

It's just enough, but I recommend using a good quality-made 750W PSU. You do not need anything "bigger" than that. Not at all, unless you decide to overclock and overvolt the 780 Ti's.

 

http://www.guru3d.com/articles_pages/gtx_780_ti_sli_geforce_review,4.html

 

With two GTX 780 Ti's under full load, their PSU pulled 617W from the wall outlet. Their CPU was idling, so that means that I have to add about 125W for your CPU under full load overclocked to 4.2 GHz. So, 125W + 617W is 742W. This means the PSU is pulling 742W from the wall outlet if both the 780 Ti's and the CPU are under full load simultaneously (which is completely unrealistic). So, that means if the PSU is 90% efficient while pulling 742W from the wall outlet, then the computer is pulling 668W from the PSU. Again, that's unrealistic; your gaming power consumption will never exceed 600-650W, and that's why I recommend a good 750W PSU, and that's why I say that you don't need any more than that. However, again, this changes if you want to overclock and overvolt the 780 Ti's.

 

So, where can you order the PSU from, and what's your budget?

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  
Reply
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  
Reply
post #4 of 22
For your setup, a good quality 850w will be fine and give you some room for overclocking. I would hope you at least have a 1440p or greater monitor setup for SLI 780 Ti. It would be wayyyy overkill for a 1080p setup. I'm gaming on a single 780 at 1440p and get excellent frame rates on High settings with the games I play.
post #5 of 22
Thread Starter 
So the Seasonic is not enough, even if it has + 80gold?

Well, for the first I wanted to go with just a single 780 ti and upgrade after I have more news about the gtx 8xx.
I would pay for the Psu maximal 150€ (I would have seperate cables, not these screwed).

As monitor I use right now a ASUS VG278HE 1080p@144hz which I tweaked to 1440p.
post #6 of 22
Quote:
Originally Posted by civerol View Post

So the Seasonic is not enough, even if it has + 80gold?

 

That has nothing to do with a PSU's output capacity. It simply has to do with how much power is lost as heat in the conversion from AC to DC (from raw power from the wall outlet into usable power for the computer). That's it. Your PSU has 660W of continuous power in its capacity. The efficiency has nothing to do with that.

 

Quote:
Originally Posted by civerol View Post

Well, for the first I wanted to go with just a single 780 ti and upgrade after I have more news about the gtx 8xx.
I would pay for the Psu maximus 150€ (I would have seperate cables, not these screwed).

 

What does "the PSU maximus" mean?

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  
Reply
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  
Reply
post #7 of 22
Thread Starter 
It was a typing mistake. I would pay at most 150€ for a new Psu. smile.gif
post #8 of 22
Quote:
Originally Posted by civerol View Post

It was a typing mistake. I would pay at most 150€ for a new Psu. smile.gif


Ok cool. So again, where can you order from?

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  
Reply
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  
Reply
post #9 of 22
Thread Starter 
Well, I often order from Mindfactory.
post #10 of 22
There is a recent good video and article on youtube done by TTL/OC3D that goes over this exact question.

Quality of power supply is probably more important than power these days. All of the component manufacturers are focused on power savings these days. Modern components use significantly less power than most users believe.

I have crossfired 7950 w/ 3770K all overclocked. The fan on my AX860 does not usually even turn on which either means my PSU is broken or the draw is not hitting the load cap for the fan.
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