ATI Radeon HD 2600 Pro 256 MB

My mid-2007 20" iMac has the exact same graphics card. Although yours has to drive more pixels on your display (which is not only larger but has a higher resolution), we should be getting about the same performance.

I don't play games, at least, not high-end cutting-edge graphics-intensive games such as World of Warcraft or Starcraft II or the various "shooters" that are popular nowadays. So I can't speak to much of that. (I have played the Starcraft II demo and it worked fine. I played World of Warcraft a few years ago and it worked fine doing that, too.)

For all my day-to-day tasks, I experience no issues and have no particular problems. I mean, how much demand am I placing on it with DVD Player and watching YouTube videos, with a little iMovie thrown in now and then?

If you're not happy with your Mac's performance with Lion, be sure you have at least 4gb of RAM in your machine. No Mac I've tried is happy with Lion if it has a Core2Duo processor and only 2gb of RAM. Also, after your Lion upgrade, give Spotlight time to finish indexing. And I found that my system sped up a few days after my Lion upgrade; I don't know why, but it might have something to do with a background process that builds an initial Versions database.

I can only tell you my experience with my specific Mac, and I have not seen those issues. I've installed Lion on a alot of other Macs also, and while I have been experiencing some problems with some (Time Machine backups taking forever or otherwise glitching is the big one; Mail's Dock icon not updating the unread count properly, and a few other minor things) none have been bad enough to make me regret upgrading to Lion on my personal machine.

It means that card can't be used for specialized parallel processing tasks which attempt to use a GPU (the processor on your graphics card) as an additional CPU. Don't worry about it; you probably don't have any applications which use OpenCL anyway.

Try this solution by Harkaitz : https://discussions.apple.com/thread/3198002?start=45&tstart=0 (5th item)

I'm still waiting for the 10.7.3 and hope this bug fixed.

"Address a graphics performance issue after sleep on some earlier iMacs that use ATI graphics"

Thanks, Apple!