I use a flashed a HD 4870 in my 2008 Mac Pro which has always worked fine with OS X 10.5 and my good old VGA monitor. Since I installed SL, this combination does not work as well anymore. I get a picture during startup (grey apple logo), but once the system finishes loading and the login window should appear the display turns black and shuts down. When I add the 2600XT in order to get a picture, I can see in the system profiler that the 4870 is correctly recognized (including its 1024 Mb RAM) but it says "no display connected" on both connectors... Therefore I think it's a software issue. SL seems to have problems in recognizing the display connectors of the card... Is there a fix to this problem? Is it e.g possible to install the old 10.5.9 drivers in Snow Leopard?