I'm trapped in 10.5.2.
Here's the problem:
When I got my machine, it ran perfectly. Leopard Graphics
Update 1.0 introduced some graphical glitches (flickering).
I reinstalled - glitches gone. Stupidly, I later installed
10.5.3. It causes the same problem that the graphics update
caused.
I've spoken to Apple. They suggest trying the ATI HD2600XT
firmware update. The thing is, a lot of people are awfully
unhappy with that update:
http://discussions.apple.com/thread.jspa?threadID=1436811
I don't want to be unhappy too, so I'm not going to apply
that update in the knowledge that it can't be reversed.
So it looks like I'm stuck in 10.5.2 (after I reinstall)!
