Hi MrFilson,
I'm glad you found this thread, which covers a log of your questions. If you get a chance, take a look at some of the linked reviews in the earlier posts, as they might help lift the fog hovering over all of the options (or make it worse. ;-)
There is someone out here who just got a fairly beefy MacPro...so I am hoping they will be able to run some bookmarks to help us all see how well PS uses all of that horsepower Apple crammed into that little trashcan. ;-)
http://www.agisoft.ru/forum/index.php?topic=2056.0From what I have found in general on the Mac, if there is a part of the PS pipeline that can use all of the CPU cores, it certainly will do so. The GPU usage is a bit harder to predict, at least with the 'built in' options from Apple. The GPU in the iMac doesn't seem to be nearly as powerful as if you had a decent midrange model for a PC. The D700's of the MacPro 'should' be relatively equivalent to the popular PC GPU cards on the threads here...but I haven't heard yet just how well PS takes advantage of them on the Mac side (especially if it uses both of them efficiently).
I think some of the debate about the best number of cores is centered around top clock speed vs. number of active cores. Since PS accesses the hardware in various ways through its steps, you sort of need a good all around performer (ie. fast when using only one core (single thread), but still be able to spin up to as many cores as possible for multi-threaded operations)...which seems to be either the 6 or 8 core machines as that sweet spot.
Maxing out the RAM to 64Gb will help for your larger image count projects and the 1TB SSD will allow you to keep more data on a VERY fast storage system. But a decent speed external drive or array certainly would also be fine in most cases. Most likely the D700 GPUs will give you better performance for PS as well.
It's just hard to tell 'exactly' how much of a benefit any of the MacPro configurations will be over the others, a top end iMac, or a build it yourself PC. I'm hoping some benchmarks will start to appear at some point.
If you do go with a PC, the majority of people here seem to use them happily. I think the best bang for the buck can be had there if you go with a 4930 or 4960 CPU with the Radeon 290 GPUs and 64GB RAM. But someone like Wishgranter could probably answer that better than me. I've been hoping that the Hackintosh community will come up with a stable and easy to configure game plan for this type of config, because it seems like the best compromise for us Mac heads.
Cheers, -C
oh, I see you found the delay in the MacPro availability...sorry. The iMac should still serve you quite well for a while, and you could always sell it off and upgrade to the MacPro once it's a bit clearer what config is best and if it would yield enough of a boost for you.