Over 4 gigs in 32bit OS.

[gurusan]

i think that if the game supports it and crossfire is working properly and rendering in tile mode then there is actually 1gb texture memory available. I could be wrong though but that's how I understand it.

[Apokalipse]

Originally Posted by gurusan

i think that if the game supports it and crossfire is working properly and rendering in tile mode then there is actually 1gb texture memory available. I could be wrong though but that's how I understand it.

no, even tile mode doesn't split the textures.
They're both running the same game (together), and both have to be ready to render any part of the game at any particular time. Which means having all of the textures that the game specifies for the particular map/level/whatever

[gurusan]

hmm ok that makes sense....but then what allows you to use cards with different amounts of texture memory?

[alexsabree]

I'm guessing that it scales to the lower card with lower amount of memory or the gpu with less amount of ram will have to borrow some ram from the system and suffer a major performance decrease.

I doubt cross-firing different chips works to well, but idk for sure.

[Apokalipse]

Originally Posted by gurusan

hmm ok that makes sense....but then what allows you to use cards with different amounts of texture memory?

each GPU/card renders its part (or parts) of the screen independently; then one of the cards joins each cards part (or parts) together

Even if they have different amounts of texture memory, each card would render their parts the same way as they would without crossfire; If a card doesn't have enough local memory to store all its textures, it would have to acccess textures from main system memory.

If one card has less texture memory, and it has to use main system memory, it's probably going to run slower than the one with a higher amount of texture memory, and therefore it will slow down the other card, if it has to wait longer for all the rendered data.