Several other drawbacks to the iMac or any other all-in-one computer system:
1) The GPU cannot be upgraded at all (at least not internally). In fact, iMacs cannot have their AMD (formerly ATi) GPUs disabled at all. And Premiere Pro CS5.x supports only NVIDIA CUDA GPUs for MPE GPU acceleration. (The current iMacs cannot be equipped at all with any GPU besides AMD/ATi.) Premiere Pro is thus forced to run in MPE software-only mode, which is much slower than with GPU acceleration.
2) No iMac has any room at all whatsoever for more than one single fast internal hard drive. Unfortunately, the interface that the iMac employs, SATA, is only a half-duplex interface (which means that data transfers can only move in one direction at a time). But video editing requires a disk system that does simultaneous reads and writes - but with only one disk connected only by a half-duplex connection, the system must wait for a given block of read operations to be completed before any writes of a given data can even begin at all. This slows down overall editing and encoding performance substantially.
3) Additional hard drives can be added externally - but the current external hard drive options available for the iMac are either very expensive or very slow. That's because the iMac has absolutely no USB 3.0 or eSATA capability whatsoever. The iMac has only USB 2.0 and Thunderbolt ports - but external Thunderbolt hard drives still cost nearly twice as much money per GB as other external hard drives, and USB 2.0 is limited in sequential transfers to only around 35 MB/s - far slower than the drives themselves are physically capable of (140 to 188 MB/s). Plus, of course, USB 2.0, like SATA, is only half duplex.
Why don't you do what the big boys are doing. Go to ADK and have them custom configure you a laptop PC computer custom designed to run Premiere and After Effects They are the number 1 expert that I know of in this field and their support is outstanding. Incidentally they sell both Mac and PC and can answer questions on performance of both systems.
HI DH i beg to differ..
Apple 17" MBP
1) 750G 7200
8 gig ram (only becuase thats all you can put in an apple)
ADK speced the same (has the ability for 16 or even 32gig ram and up to 3 internal drives) a nvidia 560 Video card
thats a rather LARGE difference
for the price of the Apple you can get one of our 9000x which has the newer 670 and desktop X79chipset/ processor
oh and a 15 the same way
Apple $2798/ ADK $1958
Thank you for the reply. If you could, could you please post the links to ADK speced MBP and the 9000x?
It's actually extremely easy for a typical MBP 2011 owner to upgrade to 16 gb of ram, even 32. Many users at the macrumors forums have done so easily. Right now the only thing holding back 32 gigs is price and availability of 16 gb ram sticks since the MBP only has 2 slots (unless the 17 inch has 4).
I also know it's possible to put 2 hard drives in the MBP, but that requires removing the optical drive. I'd love to see how 3 internal drives is possible.