OS Kubuntu 9.10 64bit CPU Phenom x4 9650 (3GHz) System Memory 4GB DDR2 Video Card + Drivers Radeon HD4850 512MB (750/1100) + 9.11, 9.12, 10.1 BETA, 10.2 BETA Performance 1680x1050 w/ 4xAA + 16xAF, everything maxed, no bloom. Game runs around 30fps, with the lowest being 14fps when there is a lot of action on screen. Have only tried the training and the infiltration missions, but from what I have seen so far the game runs great. No serious problems like crashes or game freezes, though turning off any desktop composition (Compiz, Kwin) does help in maintaining stability. Only graphical glitch so far is related to bloom and AA. If I use custom AA filters with the driver and enable bloom in the game, scenes render upside down. Regular AA filtering (box) and bloom work fine; custom AA filters (narrow tent, wide tent, edge detect) and no bloom works fine. The in game AA and AF controls don't seem to work, so forcing filters with the driver is the only way; but I seem to remember this being an issue with the regular Doom 3 engine.