ok so heres what i know. i know that i can link cards together, i know that they have to be more or less of the same type. i also know that the faster one will operate at the speed of the slower one. so heres my question. before i go and purchase another card, how close do they have to be? here is my delema. i have a leadtek PX7900GT tdh geforce 7900gt 256MB Gddr3 PCI Ex16. i can notfor the life of me find another of the same type, i have looked and not even newegg carries it and since leadtek dosnt i am out of a n option to get the exact one. if i get one similar, how similar does it have to be? for example, if i get the Leadtek WinFast PX7900GS TDH 256MB Geforce 7900GS 256-bit GDDR3 PCI Express x16 HDCP, what kind of perfomance will i see. or will it work.

You might need to go to the nforce forums. They will be able to provide you a bit more infor (I would think). Also, got o SLIZone - that has specific info about SLI...

http://forums.nvidia.com/index.php?showforum=24

http://www.slizone.com/page/home.html

Hope that is somewhat helpful.....

thanks i will try that

I think I heard somewhere that they recommend the same card, but what really matters is that the gpu core needs to be the same. I think you would be ok, but the actual sli forums will probably give more info.

The important part is that you have the same GPU core, as nforce mentioned. So you cannot pair a 7900GT with a 7900GS. It does not need to be the same manufacturer, so you can pair a 7900GT from Leadtek with a 7900GT from, say, ASUS. The clock does not need to be the same either. You can also use graphics card with different amounts of memory, though it is not officially supported by nVIDIA and you have to enable it in the registry.

A GS actually would work. You just wouldn't get as good of performance as a GT.
Just like someone I know has a 6600 and a 7800.

6600 and a 7800 sli-ed??? that cant work, totally different cores. right?

(im not an expert at sli cause i don't have it, but that doesn't seem right)

Using two graphics cards is not the same as SLI. SLI is to combine the performance of several nVIDIA graphics cards to output to a single source. You can use several different graphics cards, like a 6600 and a 7800, at the same time but you won't be able to run them in SLI.

Now I'm getting interested in this topic. So even if you have two graphics card in regular pci slots would they both be used by the computer, or only the only the monitors plugged into?

I also wondered about a motherboard I saw that had 3 pciex16 slots. Can you do SLI with that, or is there some other reason.

Sorry for butting into this topic, but now I'm very curious.

SLI requires: two nVIDIA graphics cards with the same GPU and with the SLI logic built in, two PCIe x16 slots, a motherboard which supports SLI.

What SLI does is that you have both the primary and secondary graphic cards working together to generate frames for the monitor plugged into the primary graphics card. This can help the FPS you get.

You can have multiple graphics cards without SLI to output to different monitors. The the primary graphics card outputs to the monitor plugged into the primary graphics card and the secondary graphics card outputs to the monitor plugged into the secondary graphics card. The FPS on the primary monitor depends on the primary graphics card and the FPS on the secondary monitor depends on the secondary graphics card. These cards does not need to be the same or use PCIe x16 slots.


The PCIe x16 isn't in any way a graphics card only slot like AGP. You can stick any type of PCIe card in it. AMD released a stream processor a while ago that goes into a PCIe x16 slot. You might also stick a physics card in it. nVIDIA has built in some kind of physics processing capabilities into the G80. You can get a third GeForce 8800 and use it as a physics processor.

Whoa. I've searched for that. Link please?

You mean this one? AMD Stream Processor