7900 & 7800 sli

[ramdor]

Just a quick question. Is it possible to run a 7900gtx and a 7800gtx in sli mode? Or are they two different gpu's and hence not sli compatible?

Cheers,

Richie.

 

[pastymuncher]

Sorry, but no you can't. They have to be the same GPU, ie, 7800gt, 7900gt etc and preferably the same amount of memory. They can be from different manufacturers with different bios revisions though.

 

[Lewcifer]

They don't have to have the same amount of memory. You can run a 256mb and 512mb 7800GTX in SLi, but the 512mb card just reverts to the lower speeds of the 256mb card.

 

[Lanz]

Theres nothing technically to stop u using different cards, and I've read Nvidia are working on a solution, so it might work one day in the future.

 

[FrankJH]

Also there is no stopping someone right now pairing a GT with a GTX (just incase they were thinking these are different GPU's they arent) of the same generation

 

[ramdor]

cheers for the info guys

 

[pastymuncher]

I got this from Nvidias website.

Can I mix and match graphics cards?

In order to provide optimal symmetric scaling, SLI Technology requires the NVIDIA GPU to match. For example, a GeForce 7800 GTX must be paired with another GeForce 7800 GTX. Likewise, a GeForce 6600 GT must be paired with another GeForce 6600 GT. However, using the latest Release 80 Graphics Drivers, NVIDIA GPUs sold by different manufacturers can be used together in SLI Mode. For example, a GeForce 7800 GT from vendor ABC can be matched with a GeForce 7800 GT from vendor XYZ.

Can I mix and match graphics cards is one of them is Overclocked by the Manufacturer?

Yes. A GeForce 7800 GTX that is overclocked (for example BFG GeForce 7800 GTX OC) can be mixed with a standard clock GeForce 7800 GTX.

Can I mix and match graphics cards with different sizes of memory?

While it is not recommended, NVIDIA does offer this flexibility using Coolbits. When purchasing a second graphics card, you should try to match the memory size so that you are ensured full value and performance from your purchase. For example, if your first card is a GeForce 6600 GT with 128MB of memory, you should purchase a second GeForce 6600 GT with 128MB of memory. However, using Coolbits (value set to 18), customers can force both of the cards to use the lower of the two memory sizes and operate together in SLI Mode. When dissimilar memory sizes are enabled to work together using Coolbits, the effective memory size for each card becomes the smaller of the two memory sizes. Instructions to enable this feature can be found here.

According to that you cannot mix a GT with a GTX and i have certainly never seen it done on any review sites anywhere.

 

[Vai]

What annoy's me is that I have had a 7800GTX for a while now, and I now want to run games a little faster, so I look on the OcUK page, but I don't see the 7800 series on there anymore, have they stopped being made? Seems to defeat half the point of SLI to me (I don't like buying/using second hand hardware)

 

[Lanz]

Well yes, that is where SLI is flawed. As graphics cards only last about a year in retail now until they are replaced by a newer model.

2nd hand is the way to go.

 

[pastymuncher]

There are quite a few places still selling 7800GTX's and some for a very reasonable price too. I have found one place selling the Albatron GeForce 7800GTX 256Mb version for £230.28 inc. Saying that the same company is selling 7900gt's for £175 inc.

 

[FrankJH]

I have seen Overclocked GT's paired with standard GTX's successfully - albeit some time ago and I can understand nVidia not recommending it cuz I am sure it may be down to luck of the draw - but it can work

 

[man_from_uncle]

I have seen Overclocked GT's paired with standard GTX's successfully - albeit some time ago and I can understand nVidia not recommending it cuz I am sure it may be down to luck of the draw - but it can work

I'd have thought the memory would be the issue as the gtx's memory has tighter timings or some such than it's gt counter-part. I imagine though that some of the gts, maybe from Gainwood, have the slightly better memory.

Having said that if the GPU is the only factor of compatibility....well I suppose there could be a way. Might involve a BIOS flash or something to get the gt to think of itself as a gtx.