PSU for 680 SLI with 690

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CthulhuDreams

Weaksauce
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Feb 8, 2012
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Hi, would like to ask you guys if my seasonic x-series 850 watt PSU is capable of supporting GTX 680 + GTX 690 in SLI mode.

i7 3770k with H100
z77 sabertooth
4x4GB 1866mhz ram
3 7.2k rpm HDD + 1 SSD
optical drive
2 normal fan
1 fan with LED.

I tried using PSU calculator, it shows about 668watt which i find it too low to be true. Would like to seek a second opinion here.

Thanks! ;)
 
I don't think you can SLI those two cards. How about three-way 680 SLI?
 
Yea, it is, but it's not the same as having 2x680.

Not to be cynical, but SLI itself seems complicated...much less what essentially is heterogeneous SLI like what you're suggesting.

2x690 is, of course, totally different. Depending on your CPU and other stuff, 850 might be pushing it. A 680 draws roughly 200-250W if memory serves. And the 690 is of course going to draw more.
 
CthulhuDreams said:
Hi, would like to ask you guys if my seasonic x-series 850 watt PSU is capable of supporting GTX 680 + GTX 690 in SLI mode.

Thanks! ;)
Click to expand...

Do you mean
1) 680 SLI (dual GPU setup)?
2) 2 690's in SLI (quad GPU setup)?
3) 690 including a separate 680 SLI setup in the same system?

1 = 850W power supply should be enough.
2 = 850W power supply should be enough.
3 = 1200W power supply would probably be best.

Anyway, why do you want a strange setup like 3? I don't know know that you can match a 680 SLI setup with a 690. I would assume you cant with a specialty card such as the 690 without using modded drivers. I believe SLI requires two of the same card model anyway.

Are you actually connecting the 690 to the 680 SLI? If so, why? I think you are asking for trouble with modded drivers personally =/
 
Whach said:
Do you mean
1) 680 SLI (dual GPU setup)?
2) 2 690's in SLI (quad GPU setup)?
3) 690 including a separate 680 SLI setup in the same system?

1 = 850W power supply should be enough.
2 = 850W power supply should be enough.
3 = 1200W power supply would probably be best.

Anyway, why do you want a strange setup like 3? I don't know know that you can match a 680 SLI setup with a 690. I would assume you cant with a specialty card such as the 690 without using modded drivers. I believe SLI requires two of the same card model anyway.

Are you actually connecting the 690 to the 680 SLI? If so, why? I think you are asking for trouble with modded drivers personally =/
Click to expand...

I meant SLI my current 680 with a new 690. So that means for nvidia, in order to run in SLI mode, both card must be the same?

I wasnt gona look for modded driver, too much trouble. Guess i will just get a 2nd 680 or wait for 2013 for 790.
 
CthulhuDreams said:
I meant SLI my current 680 with a new 690. So that means for nvidia, in order to run in SLI mode, both card must be the same?

I wasnt gona look for modded driver, too much trouble. Guess i will just get a 2nd 680 or wait for 2013 for 790.
Click to expand...

Yup. nvidia SLI requires the same GPU model card. Only AMD cards can be crossfired with different model combinations (well, certain specific combinations). If you wanted TRI-SLI, you could go with 3 680's, - that is possible. It would be essentially the same as the 3 GPU combination you were going for, 680 (1 GPU) + 690 ( 2GPU). If you do go for SLI, make sure the PCIe lanes on your motherboard have enough bandwidth to let them breathe!
 
At full load you're looking at 3x 195W (GTX 680) + 1x 77W CPU + remaining components. Count on needing at least 760W, maybe even close to 800W depending on the power draw of the motherboard, fans, and other little things that will add up.

As for being able to run 3 GPUs though? You're probably screwed in that the Z77 platform will run at x8/x8/x4 with three GPUs (or x8/x8/x1 if you are using any of the other PCIe x1 slots). The third card is probably going to get starved for bandwidth.
 
night_2004 said:
At full load you're looking at 3x 195W (GTX 680) + 1x 77W CPU + remaining components. Count on needing at least 760W, maybe even close to 800W depending on the power draw of the motherboard, fans, and other little things that will add up.

As for being able to run 3 GPUs though? You're probably screwed in that the Z77 platform will run at x8/x8/x4 with three GPUs (or x8/x8/x1 if you are using any of the other PCIe x1 slots). The third card is probably going to get starved for bandwidth.
Click to expand...

Some of those big boards have, I'm assuming, one of those PLX chips to add more lanes.
 
PLX chips allow for cross-GPU communication to not hog up the bandwidth used by the CPU to communicate with the GPU by, essentially, performing time-division multiplexing between the CPU/GPU and GPU/GPU talk. It won't alleviate the problem associated with low bandwidth on the third slot.
 
CthulhuDreams said:
Hi, would like to ask you guys if my seasonic x-series 850 watt PSU is capable of supporting GTX 680 + GTX 690 in SLI mode.

i7 3770k with H100
z77 sabertooth
4x4GB 1866mhz ram
3 7.2k rpm HDD + 1 SSD
optical drive
2 normal fan
1 fan with LED.

I tried using PSU calculator, it shows about 668watt which i find it too low to be true. Would like to seek a second opinion here.

Thanks! ;)
Click to expand...

The PSU calculator is pretty inaccurate. Wattage differs in real-time usage and if the PSU is even able to output it's rated wattage.

From rough estimation, I'd advise you to get no lower than a 1000W. 680 in SLi is fine for 850W, but not Tri SLi or in your case, 1 690 and 1 680. But again just like everyone has mentioned, only if you are able to SLi all these babies together :p
 
I am pretty sure that even for Triple SLI 680s you are fine with 850W PSU:

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Article in case you want some background.
 
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