With the latest web drivers, I have this issue where after a few seconds of running something that uses HW acceleration (like firefox) the display becomes super glitchy with flickering and partial inversions within the window I am working in. I don't have a ssdt patch for the card and I have tried both the AGDPfix and the Lilu+graphics kexts methods to solve the black screen at boot issue. This is with displayport and imac 17,1 I attached an ioreg *update, also glitches after working with it for a while even if I don't put it to sleep. Card not overheated or anything. not even warm. SSDT for GFX1 doesn't chance anything. No problems in windows, tried benchmarking it also before sleep in osx, no problems until you hit this magical glitch. For what its worth, it takes one click to wake the computer up, another to wake the display up First aid for the time being: go to preferences > mission control > hot corners set one corner to sleep displays, use it whenever your card goes bonkers, it comes back working. –credit to @aol in the pascal driver thread, don't rely on it though and save your data, I had one instance where I couldn't get them working again. Log Out and Log in back again, though above is much easier and can be done without seeing credit to @morrism later in the thread, you can also make an app follow a script like the following that some people found more effective. I'm also attaching it as an app. You can then use Automator to create a service that will launch this application and bind it to a keyboard shortcut using the keyboard menu in sytem preferences. Code (Text): tell application "System Preferences" --no activate set current pane to pane "com.apple.preference.displays" end tell tell application "System Events" tell process "System Preferences" tell window 1 click radio button "Scaled" of radio group 1 of tab group 1 delay 1 select row 2 of table 1 of scroll area 1 of tab group 1 delay 1 select row 1 of table 1 of scroll area 1 of tab group 1 end tell end tell end tell quit application "System Preferences"