There appears to be a ton of hubbub on the internet regarding the 27" iMac, Snow Leopard, and terrible performance when using Flash. As with most reports, this has begun to spin out of control and it seems like the blogs of the world like gizmodo and macrumors are jumping on the story.
Well... one thing the "informed" reader would notice is that NOT everyone is having this problem. Being a software developer, the computer geek that I am, and also the skeptic that i am, I don't believe in one-off issues. Usually, there is a repeatable pattern that leads to widespread issues - if everyone isn't having the problem, it's more unlikely that it's the hardware causing the issue (barring manufacturing defects).
So... I decided to test this issue. Guess what - at first I thought I had a problem... In fact, I noticed that typing in any application could be downright slow, and sometimes would lag many characters behind what I had typed. Looking at my handy dandy iStat monitor - I saw that the finder was spiking up and down in processor usage... as low as 0.2%, as high as 104%
So then I think to myself... what the hell could be causing this? Being the pragmatic fellow that I sometimes am - I decided to start disabling some of the handy dandy utilities that I had running in my menu bar, and anything else that I have installed that might be running in the background.
One by one I shut off utilities - smcFanControl, my DropBox menu bar icon, etc.. etc... But performance still suffered. So then i did it - I shut off and uninstalled iStat. Guess what, shortly after shutting off iStat - my computer seemed to speed up. I popped up a terminal window, ran "top" and sure enough - finder usage returned to normal (less than 1%).
The moral of the story... if you're having problems with your new 27" iMac - look at the software you have installed and running. Chances are you're using something that might have worked fine in Leopard, but is not ideal for Snow Leopard. Now... I was using the latest version (2.0) of iStat - which says it works for Snow Leopard - but.... something tells me this is not the case.
I am assuming that for many, this is the same case. Many people are saying "Well, my 20" iMac works Great" - but chances are their 20" iMac ran Leopard, and they installed all of their leopard tools on their new Snow Leopard based iMac.... which is not a 1:1 so far as compatibility is concerned.
Until they can prove to me otherwise, my beloved iStat is not installed on my iMac - and everything is running wonderfully.
The moral of the story here - If you are suffering from performance issues on new hardware, test again on a bare environment before you go blaming the hardware. I'm not saying that there definately are no problems with the new iMac - but I do believe there is enough "different" about it's config and it's O/S that perhaps something you are doing is causing the issue.... Unless everything is constant, "It always worked on my old machine" is not a valid statement.