SLI w/ 2 different GPUs: Is it possible?

[Ikki]

For the part where I ask for advice, skip down to the bold.

Hi everyone,

I recently ordered a 7800GT (among other things) at a computer shop that belongs to a friend's father to add SLI-compatibility to my comp. However, knowing my friend's dad, he would encounter some problems, as he was also the one who ordered the parts for my gaming rig. I'm not going to be specific with it, but let's just say that the previous problems involved the exchange of almost every single component I purchased. (I was there when he placed the order online, so I know it's not HIS fault; it's just his supplier that screws things up)

Anyway, a few days ago I got my order: Razer Copperhead? Check. Logitech G15 keyboard? Check (OH YEAH! :lol: ) USB-powered fan? Check.

My 7800GT card? Che--wait a second...

7800GTX.

That's right.

They sent him a 7800GTX instead of a GT, and charged him the same price.

Now, back when the 7800GT and GTX were new, I would have had no problem with that. I wasn't looking for an SLI connection then, so it would have been icing on the cake to have a better graphics card.

But NOW? It basically screwed me over, seeing as you need to have 2 cards of the same type for SLI to work. It looked like I was going to have to exchange it again, but the supplier thinks that my friend's dad is some sort of scammer due to him constantly exchanging his stuff for what he actually ordered (ironic, eh?). I'm certain that my friend's dad could get the supplier to exchange it, but knowing how stubborn they are, it could take a few days, maybe even a week or two, and I want my SLI ASAP. My friend's dad told me that he would charge me for the GT if I found out a way to make it SLI compatible.

Not knowing what to do, I asked a few friends, to no avail. I checked the NVidia page looking for answers, to no avail. The only contact info I found was for Mad Mod Mike's advice, so I emailed him about the situation. This is what I got:

Sorry but in order to enable SLI Technology, you must have two SLI Ready cards with the same GPU. Both will need to be 7800GTX, OR two 7800GT's.

However, every rule was made to be broken... my friend had nearly the same problem. He had a 6600GT card, and got a 6600GS from another friend who was upgrading to a 7950 system. For free (lucky man). Somehow, he managed to hook up the two to work in SLI mode... so I know it's somehow possible. (I know he's not lying because he has the two boxes for the cards; he even took the cards out of the system to prove he wasn't lying) My guess is that he altered the card in some way to make each card accept the other one (probably voiding the warranty, but his was pre-used, so we knew it worked anyway) but I'm not sure.

Now, my question is...

Is there any way at all you can hook up two different GPUs to work in SLI mode? ie Hook up a 7800GT and a 7800GTX to work together? It would save me a lot of time knowing if there was a way.

 

[newtist]

u cant do it with the 7800gt and the 7800gtx...they r too different. the 660gt and the 6600gs r pretty similar, almost identical, from waht i know..so its understandable how it worked. in conclusion...u cant do it..sorry

 

[Mg00C]

I'm not entirely sure but i think that as long as the cards have the same GPU you can run them in SLi. I know that the manufacture of the card, the core clock speed, and the memory speed, doesnt matter so long as the graphics processing unit is the same. I dont know if the 7800Gt and 7800GTX have the same GPU but i think they may so you can try it out.

 

[Ikki]

I really doubt that the 7800GTX and the 7800GT have the exact same GPU... I know that the manufacturer and clockspeeds don't matter, as I see many different cards with different speeds. I just need to be fairly sure that I can actually enable SLI with the 2 somehow, but even MMM said that it wouldn't work (at least normally).

 

[Mg00C]

I suggest you either return the 7800GTX for the right card or well your 7800GT and buy another 7800GTX. If they don't have the same GPU forget about it. It would be much easier to either refund or buy another card that has the same GPU as either one of the cards you have right now.

 

[darkstar782]

The main problem is that the 7800GT is a 20 pipe card while the 7800GTX a 24 pipe card.

However, it may be worth flashing the 7800GTX with the BIOS from the other card. They are the same GPU, the GT just has 4 pipes disabled.

You'll have to override nvFlash to do this, but it may well work. If it doesnt, have an old PCI card on hand to reflash its original BIOS.