Originally Posted by ZeroWashu

I have an iMac (C2D 7600GT 256mb) with a 24" screen running at 1920x1200. The HDD speed is 7200rpm which most Macbooks won't have.

Under X I can average over 35 FPS in Dalaran and have no noticeable issues with performance in Naxx or any five man instance. However if I turn on Shadows (slider anywhere but far left) I have the equivalent of MS Paint. Window mode has no noticeable effect, meaning I can play that way all day.

Under the XP client performance is generally worse; subjective I know but it feels jerky when lots of spell casting is going on; but at least I can use shadows without cratering performance though I still take a hit. I would say the average FPS is about 5 to 8 less than under X but isn't truly noticeable in overall play.

My choice is to always play under X. The primary reasons are smooth transition to and from windowed play and if for some reason I lock up I can ALWAYS kill the client and be back in under 15 or so seconds which is important when your relied up. I have had a few odd conflicts with some plug ins and that is the reason I have both clients on the iMac and the problem exists under both so their handling of LUA appears identical.