I'v run into strange a problem playing streaming video from Netflix on my Apple branded Radeon 4870. Both Safari and Firefox crash when I try to stream Netflix video. Live connecting (i.e, without rebooting) either of my two displays (see sig) to my other card, Nvidia 7300GT, also results in a crash, irrespective of which of the displays is set as the main display (i.e., one to which the menu bar is tied). However, if I unplug from the 4870 and restart the browser (viewed on the display plugged into the 7300GT), I'm able to play the video. If I then reconnect the other display to the 4870 and move the Netflix window to it, I'm still able to play the video. Yay! Unfortunately, when I quit the browser and attempt to stream Netflix video again, I get a fail! 
When this first happened, I thought it was because my 30" ACD is not HDCP compliant; however, as you as you can see from the above description, that's not it (admittedly, Netflix video is not HD quality, so probably not subject to HDCP constraints).
I have no problems playing Netflix video through the 4870 directly (without the unplug/plug workaround) when I'm in Windows via Boot Camp (Win7) or Fusion (XP). On the Mac side, I'm having the same problem both in 10.6.2 and 10.5.7.
When this first happened, I thought it was because my 30" ACD is not HDCP compliant; however, as you as you can see from the above description, that's not it (admittedly, Netflix video is not HD quality, so probably not subject to HDCP constraints).
I have no problems playing Netflix video through the 4870 directly (without the unplug/plug workaround) when I'm in Windows via Boot Camp (Win7) or Fusion (XP). On the Mac side, I'm having the same problem both in 10.6.2 and 10.5.7.