I have an ASUS Radeon HD7850 with 2GB of VRAM. I'm on Yosemite 10.10.2, using Clover. Yosemite only reports the GPU as a Radeon HD 7xxx 2048 MB, and I don't think it's being fully accelerated. I've been looking all over but I have no clue what to do. I've used tai-personality.pl, used radeon_bios_decoder, redsock_bios_decoder, and I've set Clover to inject ATI and use the Aji frame buffer. This made my computer screen go black after the boot bar, and sleeping and waking the computer did nothing - same with the Futomaki frame buffer. I downloaded a modded AMD7000Controller kext for an HD7850 and used inject ATI + Aji frame buffer, but when i restarted, my screen was not the right resolution, colors were off, everything was laggy. OS X reported the GPU as an HD 7850, but with only 7mb of VRAM, so obviously that kext was incompatible. What do I do for full acceleration? I've attached my DSDT, my radeon_bios_decoder output, and my redsock_bios_decoder output.
EDIT: Turns out I wasn't in sleep mode. When the computer actually went to sleep and I used the Aji profile, and waked up the computer, the screen turned on and Yosemite reported it as an HD7850 2048 MB. So now I just need a solution on how to keep it this way, without having to always restart.