Not positive on the 5870 but with other cards you can mix ones with different amounts og VRAM but the cards will only use the amount of VRAM that the lower card has (thus you would be wasting the 1GB of VRAM on the second card when in Xfire.
I guess we will find out. I have a 2gb 5870 on order and didn't even bother to think about the compatibility issue until I saw that youtube video. Worst case senerio I sell the 1gb 5870 and get a second 2gb.
@^ Didn't you read what they said? It would scale down meaning the watts required would be less. @brennon7 The thing also with not having a higher psu is that there is no means of overclocking available cause there may be a chance for your power supply to break down and cause your computer to break down also.
Youtube videos? really?
Get 10.5, apparently it fixed the bug with crossfire and eyefinity.
That youtube video is MY video of the single 2gb 5870 and the performance I'm getting out of it.
There is not issue with crossfire and eyefinity I have been running crossfire cards and eyefinity for MONTHS started with 5850s and then 5870s. This thread is about mixing a 2gb 5870 with a 1gb 5870. There is no issue when the cards are the same. When they are different that is when it FAILS.