I'm having all kinds of issues. I have now re-installed Windows and applied all updates and installed MB drivers and then Catalyst6.5 and it still doesn't work. ATI are being useless. Please would someone out there describe their working setup so I can see where I deviate? It's incredibly frustrating trying to prize diagnostics info from ATI I need to know things like: 1) What is your motherboard? 2) What are your cards? 3) Where are your cards plugged in (PCIe slots)? 4) Where are your cables plugged in (which external sockets)? 5) What appears in your Device Manager Display Adaptors list? 6) What is listed in your devices drop-down in CCC? 7) What version of Catalyst are you using? 8) OS? 9) Anything else you think is relevant? My answers: 1) A8R32-MVP Deluxe 2) Sapphire 1800XT Master and Slave 3) #1 (Blue) and #2 (normal) respectively (I might play with this. Now I think about it I'm not *certain* they are in right and some have said they have had similar symptoms with them in backwards...) 4) Currently using slave socket diagonally opposite the output from the master, though it doesn't seem to matter 5) The fab four 1800 master / 1800 master secondary / 1800 / 1800 secondary 6) Just one: 1800 master with no monitor listed even though monitor drivers are set (device shows as Illyama E511S), I've read some have all four showing? Or was that just in the 'extended desktop' 'screens' graphic thing? 7) 6.5 8) Windows XP with all updates applied. 9) I've had Crossfire 'working' with either slave socket being used and ATI docs says this isn't possible. Have I ever had it really 'working'?... My symptoms (in case anyone can help): Crossfire *did* work to begin with, though it was 'odd' - 3DMark scores were bad - perhaps due to conflicts with a wireless network card (now removed) and a mis-synching processor (now patched). Whilst I was fixing those other issues, it started getting more generally flakey, i.e. would, on windows starting, complain a 3D app was running and would disable crossfire and then disable the "enable crossfire" checkbox. This would 'fix itself' after various, random actions (just reboot, reinstall of CCC, changing the slave socket, etc.) but then disable again after N reboots. Now, it will not come back no matter what - I even reinstalled Windows. Any help VERY gratefully accepted - I'm currently facing sending the PC back to Vadim. After investing dozens of hours in trying to diagnose it myself, I wanna get to the bottom of it!