[Davros]

An article on it
http://www.bit-tech.net/gaming/2009/...orting-games/1

a quote
"That said, implementing multi-GPU support is apparently a pretty simple job in games. “It's generally invisible to us,” says Bozz"

If thats the case, how come you cant run a game in xfire mode unless ati have made a profile ?

[Demirug]

Originally Posted by Davros

An article on it
http://www.bit-tech.net/gaming/2009/...orting-games/1

a quote
"That said, implementing multi-GPU support is apparently a pretty simple job in games. “It's generally invisible to us,” says Bozz"

If thats the case, how come you cant run a game in xfire mode unless ati have made a profile ?

If there isn’t a profile the driver will use a generic xfire mode. Unfortunately there are many things that an engine can do that kill xfire completely. And as the additional driver checks requires more CPU power you can even end slower.

A xfire profile disable these checks when it’s know that the game doesn’t such bad things.

[Humus]

Originally Posted by Davros

If thats the case, how come you cant run a game in xfire mode unless ati have made a profile ?

Of course you can. My demos usually scale well with CrossFire and they definitively do not have a profile. It's all about whether the game has any interframe dependencies or not, and mostly where in the frame you depend on somethings from previous frame and where in the previous frame that data was finished. A dependency from somewhere in the frame to the same point in previous frame is generally not a problem for 2 GPUs, but will be a problem for 3 GPUs or more. A dependency from the beginning of the frame to the end of last frame will generally kill all scaling. Fixing it may or may not be easy.