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I just picked up the i7. I am coming from a quad 2.66 Mac Pro with 6 GB ram.

I knew the iMac i7 would be faster, but I wasn't prepared for how much faster. This thing screws. It absolutely SCREWS. I could get about 40fps on Handbrake encodes with the Mac Pro, and the i7 was hitting about 185fps peak. Everything runs smoothly, and all the Steam games run at native resolution without any stuttering.

Get the i7.
 
Thanks for posting on the outcome! I get a little disappointed when people ask a million questions then never respond again to the forum about how it worked out.

I was also going back and forth too, and as a pretty active gamer, I'm looking forward to the i7 chip when I buy my new iMac. But that won't be until they update the video card, so I'm prepared to stick it out on my iBook G4 (lol) until they launch it.

Disclaimer: Expecting someone to say that Macs suck for games, the games I play are generally universal, from Blizzard and now Valve.
 
Universal games still don't take away the fact that osx has more out-of-date drivers compared to windows, and one usually experiences higher gaming performance in windows.
 
if you edit your HD video with a program that allows for hardware encoding, you will notice better encoding speeds, but this is still mostly done by the GPU, so the processor won't really have a significant effect on it.

That being said, I built a PC last summer with an i7 920 in in, and have used it for some HD video editing, and it's been a dream so far.

In my opinion, if you can comfortably afford the extra $200, go for it. Buying the best of the best now means less slow down later, allowing you to be able to go longer before upgrading.

But if you are balancing the expense of the extra processor with other purchasing/saving decisions that you would have to sacrifice for it, then the i5 will more than suffice for what you have said you are doing.
 
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