Need crossfire help plz!

[TheMuffinMan]

Originally Posted by Tim

Unfortunately this is not true. I tested it, and eventually found the support forum post from ATI saying that no games will work in windowed mode with crossfire.

supporting link?

[Tim]

There are a lot of posts on the AMD ATI forums about windowed mode disabling Crossfire. You can also see them on guru3d.com. Just google with site:guru3d.com blah blah and such. A few seconds of an example is here: AMD Game Forums - Sapphire 5850 in Crossfire Serious Problem Help plz!!!

1. That's because gaming in a windowed environment effectively disables crossfire settings.

Maybe there is a driver hack or such, but that is just that, a hack. AMD has clearly stated that they disallow consumers from setting Crossfire settings purposefully. They actually encrypt specific game Crossfire profiles to prevent customers from setting specifics VS. Nvidia's open SLI methods (simple .XML).

Also, it takes just a few minutes to test this out to confirm. Just install 2 Crossfire cards (Ex. 5870), enable Crossfire, run a game like Metro 2033 in Full Screen mode, verify Crossfire is working (big crossfire logo in top right + GPUs both show CPU load). Then run Metro 2033 in windowed mode, the Crossfire logo will be gone, and GPU 2 will show no CPU. Same can be said for L4D2, World of Warcraft, Team Fortress 2, and Mass Effect 2, as I tested with all of these. Crossfire works in full screen but not windowed.

I also was fortunate enough to have people in the video stream who had Crossfire cards to test as well, of which they all confirmed the findings.

I also had people test that SLI in windowed mode works, which is what lead me to return the 5870's and get 2x 480s. I can confirm that Nvidia SLI works in windowed mode, and it works on multiple games on multiple monitors, all in windowed mode.

EDIT: Oh and something else to mention, I returned my ATI cards for a full refund and wasn't charged a typical 15% restocking fee specifically because the geeky techs I bought the cards from understood and confirmed my pain that Crossfire doesn't work windowed mode, they even felt a bit bad that they forgot to mention it to me in advance as they knew I multiboxed.

Bottom line: Plug in ATI cards, play windowed mode game = fail multi GPU. Plug in Nvidia cards, play windowed mode game = Yay multi GPU.