[SOLVED] Would a 1000w Power Supply handle 2 GTX 970's in SLI?

[luzhun]

Hello. I already have 1 EVGA GTX 970 FTW graphics card in the system and am going to get a second one to try SLI'ing them together. I am just wondering if there are any precautions that should be done beforehand? I am making sure that the second GPU is an exact match having the FTW stats. I am hoping the power supply will handle the additional GPU to what everything else that is already in it. Would the motherboard just automatically recognize and accept the SLI when having that physical connection done from the top using the metal bracket or is there a setting that needs to be set or changed in BIOS or the OS? Thank you for the updates. This will be the first time performing an SLI and am doing this route to save $ mostly but also out of curiosity. Perhaps there is another graphics card out there for around the same price as what this was that has better specs?

Power Supply

Motherboard

Graphics Card

 

[Karadjgne]

Gtx970 generally pulls 160-170w, maybe 200w with OC or the FTW.

I ran a 970 OC'd to 128%, with a 3770k OC'd to 5.0GHz (1.1GHz OC) and full custom loop from an Evga G2 550w.

A Evga P2 1000w won't even blink at sli FTW 970's, you'll have @ 300w to spare.

Bios will recognise the cards, it'll be upto you to arrange the Sli from nvidia control panel. Windows 10 is mgpu (multi-gpu) based.

Biggest issue with sli (other than lackluster or zero support in modern games) is the vram. A gtx970 has 3.5Gb of fast vram and 500Mb of slow vram, which rarely ever gets apportioned or used. Sli does not Add the vram. It uses one card to render half the frame, then the other card to render the other half, while the first card gets busy on the next frame half. So all you get is basically upto 3.5Gb of vram used at any given time. That's it. In modern games, especially at higher resolution, while sli is capable of higher fps, it gets the shaft because of lack of vram.

Running a game at 4k can easily soak up 8Gb, and you have 3.5Gb reliable. You may or may not see any improvement, and it's entirely possible to see a negative result instead.

 

[jacob249358]

What are you doing with gtx 970 in sli? Very few games benefit from it.

 

[Karadjgne]

On the contrary, Lots of games, probably the vast majority of games will benefit from sli. As long as they are over 2-3 years old, basically designed for Windows 7/8/8.1 or prior. The degree of benefit is whats questionable.

My 2 favorite games are Skyrim and SwToR, both of which just hit 10th Anniversary. Not everyone plays just what's latest and greatest.

 

[Karadjgne]

Thanks for the vote-down. Obviously thinking outside the box is a new idea. Sli has been around since '98, designed by 3dfx for the Voodoo2 (I had one, amazing card if you could get the drivers to work) , which was consequently bought out by nvidia...

If you figure all the supported games for the last 24 years± , there's a whole lot more of them than recently unsupported. Almost all of the mainstream titles, popular titles etc, had some sort of support, which got you anywhere upto @ 70% performance increase.

 

[luzhun]

Gtx970 generally pulls 160-170w, maybe 200w with OC or the FTW.

I ran a 970 OC'd to 128%, with a 3770k OC'd to 5.0GHz (1.1GHz OC) and full custom loop from an Evga G2 550w.

A Evga P2 1000w won't even blink at sli FTW 970's, you'll have @ 300w to spare.

Bios will recognise the cards, it'll be upto you to arrange the Sli from nvidia control panel. Windows 10 is mgpu (multi-gpu) based.

Biggest issue with sli (other than lackluster or zero support in modern games) is the vram. A gtx970 has 3.5Gb of fast vram and 500Mb of slow vram, which rarely ever gets apportioned or used. Sli does not Add the vram. It uses one card to render half the frame, then the other card to render the other half, while the first card gets busy on the next frame half. So all you get is basically upto 3.5Gb of vram used at any given time. That's it. In modern games, especially at higher resolution, while sli is capable of higher fps, it gets the shaft because of lack of vram.

Running a game at 4k can easily soak up 8Gb, and you have 3.5Gb reliable. You may or may not see any improvement, and it's entirely possible to see a negative result instead.

WOW! Thank you so much for all of the detailed information. I did not know that the VRAM would not be combined. I was sort of hoping that would've been the case. Regardless, I am still going to try it. It does sound like the 1000w would be plenty since you had used only a 550w with your setup that you had mentioned and was able to do all of those adjustments. I am not overclocking anything. My OS is a Windows 7 Professional x64 bit instead of Windows 10. I only mostly play one game anymore. Other than Skyrim or Skyrim SE, I have been playing ESO (Elder Scrolls Online) in 4k resolution with maxed out graphic options from the game. I am seeing how much more the FPS will go up by doing this SLI or if will be more smooth when some effects are taking place.

I may end up also getting an EVGA GTX 1080 FTW 8GB, if I can find one for a great price to eventually replace both of these in the future. Do you recommend any sort of SLI bracket for these cards? I am not sure if there are different ones out there with different designs or brands that offer better link quality? I heard there are ribbon cable ones as well?

 

[Karadjgne]

Yeah, sli is about buried. It's already dead, Crossfire has been dead for years. Sli went from mainstream dreams to redundant when cards like the 1080ti could saturate 1080p without all the ups and downs sli could be with games and settings.

At 4k, whether that's real or DSR, you've pretty much maxed out the vram. Unfortunately there aren't many games that support mgpu, or you could add the vram for multiple cards. But you'd need Win10 + /DX12 for that as Win7 /DX11 was still sli based.

 

[rcald2000]

PSU Requirements for Graphics Cards
https://www.realhardtechx.com/index_archivos/Page362.htm

 

[Karadjgne]

Great tool, but take with a grain of salt. There's a big difference between a good 65w Amd cpu and a xx900K series intel, so adjustments can and should be made for outside factors.