I was in the middle of developing a Flex applcation, and then I recently switched from Windows XP to Mac. My app is noticeably less responsive on my Mac than on Windows, and today I proved it's not a hardware issue, because I ran the App on my Mac and a Window XP on Virtual Box side by side, and IS much more responsive on XP. Things like repainting in response to window resizing, selecting/unselecting list items, scrolling up and down(I do have complicated list-item-renderers). Has anyone seen this as well? Is flex/flash just not as well supported on Mac? Or are there tweaks I can do to improve performance on the Mac?
Yep, pretty common knowledge in the Mac community that Flash performance is poor when compared with Windows.
Interestlingly, this is not the case with Silverlight, where performance is comparable between implementations.
Read this entry from the blog of Adobe's John Nack, conveniently posted just yesterday. Go halfway down, you find
-- On Mac vs. Windows performance --
Finally, let's turn to a touchy subject.
If Flash runs faster on Windows than on Mac, that must be proof of Adobe's incompetence and/or anti-Mac malice, right? Of course, if Flash ran faster on Mac than on Windows, that would be taken as proof of OS X's modern awesomeness. Heads they win, tails we lose. (Come on, tell me I'm wrong.)
Despite the Flash Player team investing disproportionate resources in the Mac player (where the Mac has ~5% market share to 90+% for Windows), and despite them making big strides on the Mac, it's true that Flash performance on OS X has lagged behind Flash on Windows. That needs to change.
My understanding is that there's work that both Adobe & Apple could do to improve matters. Mac users*** complain about high CPU usage when playing video. The latest Flash Player uses many fewer CPU cycles for video, but the needed hardware decoding support isn't available on the Mac right now. I don't have any inside info here, but I've heard that the Safari team is a great group of folks, and I hope they're able to work with the Flash Player team to added the desired support.
So, alas, it's not just anecdotal. Adobe admit it. And they consider they're spending "disproportionate resources" in the Mac player.
John Gruber had a great article on this yesterday:
"I’ve been hard on Flash Player for Mac OS X, but this performance situation is not entirely in Adobe’s hands. On Windows, Flash makes use of hardware decoding for H.264, if available. On Mac OS X, it does not. This is one reason why Flash video playback performs better on Windows than Mac OS X, and also why H.264 playback on Mac OS X is better through QuickTime (which does use hardware decoding)."
He goes on to explain why this is the case and why he thinks this is what Apple wants both from a technical and political perspective.