according to macworld there is only an 8 percent speed gain for the i7 over the i5. i am not really sure you would see a huge advantage. however, this partly depends on what kind of work you intend to do i.e. HDR etc. if you are mostly doing standard photo editing stuff it won't be something you will really notice. but the usual advice for buying a computer applies - buy the best you can afford. this is even more true for the all-in-ones. if it were me i would go with the i5 and add more RAM at a later date (this will help with large file sizes). 8 Gigs would do nicely here.
hope that helps,
Thanks, PhotoJ. My thoughts exactly. I was concerned since the 8% you mentioned represents an average of different types of applications (I believe) from a broad spectrum test suite and wasn't sure which side of the 8% the large photo file handling of LR would fall on. Hopefully, any differences between these processors would be academic with this particular app.
Thanks again for your thoughts. - Andy
no problem. i also had a look at the speed scores for the various tests on macworld for the CS4 test it was a dead heat between the i5 and the i7. this is only a guess, but i think that is the kind of performance you will get with LR as well. the only exception might be when it comes to rendering previews of imported photos. if you look at that and the other tests (aperture test), it will give you a pretty good idea of what to expect (small gains at best). but if you are in a work environment where seconds count, than i would actually suggest getting a mac pro. you will be thankful you did. with the mac pro you can easily add more hard drives and it generally has a lower part failure rate (the iMac well good, is just a glorified laptop). it is also cheaper to fix in some cases. if the GPU goes on the iMac you need to get a new logic board. if it goes on a mac pro you just get a new GPU because it is on its own board. you will also be able to get more productive use out of the mac pro because it is easily updated. about the only things you can upgrade on the imac are the ram and the hard drive.
anyway, hope that helps.
PhotoJ, Thanks much for all of your recommendations. I'm reading your response with the still unopened iMac quad core i5 chip on the floor behind me! Naturally, I was happy to read your reply about the close CS4 tests. As a non-professional photographer (just a Nikon D90 and two grandkids to justify it) I do not need the ultimate power of the Mac Pro. To be honest, I have had no problems with my (also quad core) HP Windows based system currently but it is not as physically stunning as the new iMacs, nor would be the Mac Pro. Excellent WAF for the iMacs.
You are correct that I am giving up the expansion capabilities of a tower CPU but that seems to be less relevant than it used to be since a system like the iMac has a reasonably fast graphics accelerator card, sound, networking capability, etc., all of which were the reasons for the expansion slots back in the "olden days". In fact, my motivation for the iMac was largely from the excellent hi-res and color quality from our Apple Cinema HD 23" monitor. This'll bring me up to 27" and its great appearance went a long way to convince my wife to write the check ha ha!
So I made my choice and can now be finally welcomed into the world of Apple Computers after owning a computer of one architecture or another since 1981 if you could believe that. Thanks again for giving me some peace of mind over the processor choice which of course was my original post. Have a great Holiday Season. - Andy
if you are "only" shooting your grand kids and such i think you will be very happy with your choice. as i said the CS4 test results for the i5 and i7 were identical. sorry if i got a little long winded, i just wanted to cover all the bases as you did not indicate to what use you would be putting your machine. for armatures, semi-pro and pros just starting out the i5 imac is a perfectly fine choice.
i have been a mac user for nearly untold years and i currently own a macbook pro 2.8 ghz. as a professional photographer i can tell you that it eats lightroom and photoshop for breakfast (the only time i have noted a slow down is when using the graduated filter).
my only suggestion would be that before you install all your new software and so on, that you wipe wipe the hard drive (write to zero) and re-install the OS. then fix permissions. this will stave off any potential issues and make the OS very stable (the OS install that the factory does is not very good). if you don't know how to wipe the drive and write zeros over, just call apple tech support and they will help you. or go on the apple support boards.
good luck with your new machine and happy holidays!