Does Crossfire utilize memory from each GPU?

[jockey]

I've read no, and I've read yes. I have yet to receive confirmed info to back either case.
My situation is:
I'm a flight simmer into Rise of Flight. This is a very intensive GPU memory program. I have a single 1gb DDR5 5770 card. I'm looking to increase to 2gb GPU ram. Do I need to upgrade to a single 2gb card, or will an added 1gb 5770 in crossfire suffice?

 

[bystander]

Crossfire works by alternating frames between the first card and then the 2nd card. Both cards use their own memory to render their frame. As a result, you effectively have only the amount of video ram as each individual card has.

What resolution do you play that flight simulator at? I find it hard to believe 1GB isn't enough. Of course I don't play flight simulators (or at least I haven't in nearly 10 years), so I might be out of the loop here.

 

[jockey]

I play at 1080p. The game has a GPU memory usage % in the start up screen. At maxed settings, my 1gb card is at 126%, which leads to some stuttering.

 

[dumble]

i dont think it only work with 1st card memory.
i still not understand why ppl say 1 gb always 1gb..
so CrossfireX HD5770 will have 2X1GB

 

[kajabla]

GPU RAM won't be the important thing, I think. Processing power will make more difference if, as bystander says, the frames are alternated.