after you update to 10.5.7, if all works fine for you with raeonhd card – skip this tutorial
radeonhd 2×00 3×00 4870 4850 users just install this natit and enjoy – Natit pkg link
now about 48×0 users only:
Default natit posted above uses Motmot as framebuffer driver, Motmot known to have problems with powermanagement and memory clocks (results in screen shakes, affects only 4850/4830/4850×2), default natit has a workaround for this, for 4850 users.
There is another framebuffer for 48×0, called quail, it doesnt have screen shakes problem, but has less output capabilities on 4850/4830 (only secodn dvi port works as dvi, with patched quail) , here is natit which make use of Quail – Natit for Quail pkg link , use it as alternative for default natit, if Motmot has issues for you.
Now patched framebuffers: it’s patched Motmot and Quail to get rid of dvi2vga dongle trick (or hdmi2dvi + dvi2vga on some cards),
the package called “Patched framebuffers for 48×0 and 3870×2″ – recomended for 4850×2/4850/4830/ 4870 with hdmi/DP/VGA outputs
Patched ATIRadeonX2000.kext, for exotic cards like – 4830 4890 4870×2 4850×2 3870×2 , to get QE/CI , its called “QE_CI_Exotic_cards”
ATI_init pkg for MacPro users(4890 4870×2 will need the file above also, natit inside) – ATI init pkg link , two pkgs, that’s all you need.
Last thing, 3870×2 users – install default natit, patched framebuffers pkg(only if you dont have ATY_Triakis.kext installed yet) and patched ATIRadeonX2000 pkg.
Pkg with patched files available at irc://irc.osx86.hu #radeonhd channel, first link in topic
P.S. for dummies, for 4890 and 4870×2 you need to install default natit and patched ATIRadeonX2000.kext pkgs
for 4830/4850×2 you need either default natit , patched X2000.kext and patched framebuffer, or quail_natit , patched x2000.kext and patched framebuffers.