Crossfire Confusion

To start off, I have ZERO intention of running XF. I'm asking just out of curiosity. My understanding is that any pair of identical PCI-e nvidia cards can be run in SLI. But if you want to do XF, you need an XF-specific ATI card? Is that right? Do both have to be XF-specific? I was searching Newegg and found an X1900 Crossfire Edition that runs at 625MHz. So the faster X1900 cards won't run XF? Why won't just any old ATI PCI-e card run XF?

How many rooms can one heat with an X1900 XF rig? Imagine XF1900 with Peltiers!

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although some say you don't get the same performance, technically with some cards you don't need the master card. i think x1600's can run in crossfire mode by communicating through the pci-e bus AFAIK. the thing with the crossfire master cards is that they have a composition chip onboard which combines the two sets of gfx created by the 2 gfx cards. nvidia uses the gpu on one card to do that same composition but at a hit to performance. the C/F master cards also come with the special connector to hook up the two cards.

Reply to Strangestranger

Quote :

although some say you don't get the same performance, technically with some cards you don't need the master card. i think x1600's can run in crossfire mode by communicating through the pci-e bus AFAIK. the thing with the crossfire master cards is that they have a composition chip onboard which combines the two sets of gfx created by the 2 gfx cards. nvidia uses the gpu on one card to do that same composition but at a hit to performance. the C/F master cards also come with the special connector to hook up the two cards.

So the XF-specific card I found on Newegg is the master card, right? And for the second card, any X1900 card will work, even a faster card? Can the master card be overclocked like normal X1900 cards? Thanks for the info!

Reply to clue69less

yes the crossfire edition is the master card and any x1900 card be it xt or xtx will work, although i have heard that both card will run at the master card's clocks. not sure of that though. most people say to geta xt and overclock it to xtx levels so i doubt the C/F editon is any different.

Reply to Strangestranger

"yes the crossfire edition is the master card and any x1900 card be it xt or xtx will work,"

I'm not sure this includes the 1900 AIW variant, however....

Reply to mdd1963

Quote :

yes the crossfire edition is the master card and any x1900 card be it xt or xtx will work, although i have heard that both card will run at the master card's clocks. not sure of that though. most people say to get xt and overclock it to xtx levels so i doubt the C/F edition is any different.

Wrong, When running XF mode, both cards run at their individual native clock speed, (or their individual over-clocked speed that you have them set at, whether you have one or both over-clocked).
So any X1900 variant card from any brand will work with any CF X1900 card. Same goes for X1800 series... which makes them pretty flexible.
But, if you pair a XF card up with a GTO or 12 pipe model then the XF card will also disable its pipes so they both have same amount of pipelines... That is the only disadvantage, but you shouldn't be running a budget card in CF with a high end CF card anyway...

Reply to RichPLS

Quote :

yes the crossfire edition is the master card and any x1900 card be it xt or xtx will work, although i have heard that both card will run at the master card's clocks. not sure of that though. most people say to get xt and overclock it to xtx levels so i doubt the C/F edition is any different.

Wrong, When running XF mode, both cards run at their individual native clock speed, (or their individual over-clocked speed that you have them set at, whether you have one or both over-clocked).
So any X1900 variant card from any brand will work with any CF X1900 card. Same goes for X1800 series... which makes them pretty flexible.
But, if you pair a XF card up with a GTO or 12 pipe model then the XF card will also disable its pipes so they both have same amount of pipelines... That is the only disadvantage, but you shouldn't be running a budget card in CF with a high end CF card anyway...

Thanks, thats exactly what I wanted t know. Of course by the time I get ready to build XF will be long gone and something else will be the NBT (Next Big Thang).

Da Worfster

Reply to Worf101

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