I have 2 Radeon 4850's in Crossfire. I normally output to an LG 1920x1080 monitor via DVI with no problems. Today, I tried to use the same PC to connect to my Sony Bravia 46" HDTV via HDMI. The POST displays on the TV and the windows boot logo shows, but after a few minutes the boot up hangs at the "Starting Windows" screen after the colorful animation, but prior the blue "welcome to windows 7" screen. I can use the same HDMI cable to connect my wife's Mac to the TV, and to connect the PC to the LG monitor so there's no issue with the cable or the inputs on the TV. I can even get a full boot up and full display on the TV in Safe Mode, but as soon as I try to do a regular boot up, no luck.
FYI I do have all of the latest windows updates and recent Catalyst drivers (I believe 11.10 or 11). I also used this same setup last year with a single video card and had no problems booting up. (yes, I have tried the hdmi outputs on both video cards)
I was really hoping to play some League of Legends in 46" bliss this holiday.
Okay, more info...apparently, the hdmi connection to the Sony TV freezes my PC completely. I used both a DVI to HDMI cable and a normal HDMI cable to connect to the LG monitor and booted up with no issues. Then I unplugged the cable from the monitor and tried to plug it into the TV. At that point the system was unresponsive and I had to hard reset. I then tried booting up like normal and connecting the tv after the fact to behave like a second monitor and the system locked up again (mouse doesn't move, keyboard unresponsive,etc)