ATI Radeon HD 2600 XT 512 MB (Diamond) - Mountain Lion - Video Problem I'm using ATI Radeon HD 2600 XT 512 MB (Diamond) Video card with Mountain Lion installed. Using Chimera 1.11.1 as boot loader. Everything else including Sound working fine. I managed to get thru resolution 1680x1050 60Hz on DVI port using Aty_init, ATINDRV and modified ATIRadeonx2000 kexts (please see attached picture). Cannot play DVD, videos in iTunes, Youtube videos, selecting new tab in Safari gives flickering screen and new notification center flickers. I'm not willing to accept that the card is too old or cannot be used in Mountain Lion since the fact is that Mountain Lion still carries all necessary kexts for this video card. Therefore, it must work with tweaks and experts advice. I'm eager to learn and open to constructive advice. I'll appreciate if anyone can help or at least guide me in right direction.