do i need two identical cards to go SLI?

[rasczak]

I've got an XFX 7900 gtx, do i need a second card exactly the same as the first to go SLI?

 

[Dazed and Confused]

With older Sli boards yes. With newer no. And if anything flash any 7900GTX to an XFX 7900GTX.

 

[rasczak]

never flashed a video card before. how would I go about this?

 

[Dazed and Confused]

#1 Find out what version of XFX 7900GTX series you have the go here and download the proper bios.

#2 Go here and download NiBiTor 3.4a .

#3 Unzip the bios you downloaded and unzip Nibitor. Place the bios u downloaded into the NiBiTor folder ( the one that has te NiBiTor.exe in it ). Open NiBiTor and select "File" then "Open bios". Select the XFX 7900GTX bios then after it's loaded click "Save bios" then rename the bios to 7900GTX ( keeping file type as .rom ) then save it.

#4 Go download NvFlash 5.50 here

#5 Make a bootable floppy or CD ( which is highly recommended against if u have a floppy drive ), put the files for NvFlash onto the floppy/CD along with the "7900GTX.rom" bios you renamed.

#6 Restart your machine with the bootable disk in your floppy drive/CD-rom and let it load up.

#7 when the A: prompt comes up ( provided you're using a flopy disk ) type in the following exactly as it reads, including single spaces. ( If you are using a CD you'll need to switch to the CD-Rom the disc is in, which is usually "D:" )

"nvflash -4 -5 -6 7900GTX.rom"

Then hit "enter", when it asks you if you want to proceed hit the "y" key. It may ask you one more time to confirm the over write, if so hit "y" agiain.

When it's done simply restart your machine and whatever brand 7900GTX u flashed will now think it's an XFX 79000GTX

 

[DaveBC]

I'm running an EVGA 7800GTX 550mhz/1700 with an BFG 7800GTX 580mhz/1750

however, both are 512mb models

works fine

 

[TheRyuu]

Originally posted by: Dazed and Confused
With older Sli boards yes. With newer no. And if anything flash any 7900GTX to an XFX 7900GTX.

I think it's a matter of driver support, not the motherboard.
So, I wouldn't risk flashing the video card if it's not necessary.

@jpbelauskas
As long as it is another 7900GTX, you should be fine.

What you can't do is pair up say a 7800GTX with a 7900GTX. They must be of the same "family" if you will.

 

[Rage3kMoiz]

Some correction required here IMO. Only the GPUs have to be the same. The clocks speeds and third-party manufacturers may differ. For example, you can use an eVGA 7900GTX with a BFG 7900GTX, even if the clock speeds are different. But whatever card you install in the master slot, the other card will emulate its settings. So if the BFG card is in the master slot and the eVGA one in the other, the eVGA card's clocks will be brought up (or down) to match the BFG card's settings. When it comes to memory sizes, make sure you install the card with the lower memory (the eVGA 7900GTX for example) in the master slot since then, the effective memory used by both cards will be the same, meaning that on the other (BFG) card with the higher memory only the amount of memory that matches that on the eVGA card will be used and the rest will be 'wasted', so to speak.