Can I use two GPU's with different amounts of VRAM in SLI

[EllisDJ]

Hi

Can I use two 580's in SLI with different amounts of V RAM

IE one with 3gb of Ram in the master and the other (what I have with 1536)

Thanks

 

[Krony]

I read somewhere that u can't but even if u can u will only have 1.5Gb of usable Vram so the 3Gb card would be a waste.

 

[Surveyor]

According to Nvidia you can't.

Can I mix and match graphics cards with different sizes of memory?
No. For example, an XXXGT 512MB cannot be paired with a XXXGT 1GB in an SLI configuration.

Nvidia SLI FAQ


According to Tom's Hardware SLI can be quite picky:

For example, it is rather difficult to get two Nvidia cards obtained from different vendors, which deviate from the reference specification, to cooperate in SLI. From a pool of six different GeForce GTX 580 cards, only two would work together consistently. From a pool of five different GeForce GTX 570s, only three would. We had problems mixing clock rates, BIOSes, supporting platforms, and so on.

Micro-Stuttering And GPU Scaling In CrossFire And SLI

 

[harmony]

^^Thanks for the info, Surveyor. It's good to know.

 

[EVGA_Nick]

It used to be unofficially supported via Coolbits and was even in the SLI Zone FAQ but this was discontinued a couple years ago.

 

[Rroff]

I've never had a problem doing it in the past but I'd err on the side of it not being a good idea to try its a bit of a waste of VRAM anyhow.

 

[EllisDJ]

i thought you might get away with it if you use the 3gb vram card as the primary.

As thats the only card where the ram is used to my knowledge - therefore would get the full benefit but at only a % of the full cost of 2 3gb cards

has no one actually tried it???

 

[Krony]

In sli both cards have to store the same data, like i said before even if it did work u would only get 1.5Gb of Vram.

 

[Surveyor]

EVGA say it doesn't work.

I called evga with that same question and here's the answer i got: You can not SLI regular 580 with the 3GB version!

Can I use the GTX 580 3 gb card inSLI with the GTX 580 1.5gb?


Even two 1.5GB GTX 580's don't always play nicely in SLI.

For example, it is rather difficult to get two Nvidia cards obtained from different vendors, which deviate from the reference specification, to cooperate in SLI. From a pool of six different GeForce GTX 580 cards, only two would work together consistently. From a pool of five different GeForce GTX 570s, only three would. We had problems mixing clock rates, BIOSes, supporting platforms, and so on.

Micro-Stuttering And GPU Scaling In CrossFire And SLI


You could always try it for yourself and let us know how you get on.

 

[Krony]

Also what resolution do u use ? maybe u can get away with another 1.5Gb card and save some cash or sell the 1.5Gb card and buy a pair of 3 Gb.

 

[Rroff]

Even two 1.5GB GTX 580's don't always play nicely in SLI.

I found that a bit strange when reading that article - I've put together dozens of SLI systems over several generations of nVidia cards and rarely had issues SLIing cards of the same model regardless of brand, clock speeds, etc. couple of times had to flash both cards with the same firmware but thats usually an exception.