I keep hearing that people want a quad core processor, but what can it do? It is just for bragging rights. Professionals that use high end software will buy the Mac Pro for all the cores and memory.
Some hobbiests do use the horsepower too.
I'm currently running a G5 PowerMac. Probably 75% of the time, the amount of horsepower I have right now is fine ... but consider the following for why I'm planning on upgrading to a dual Xeon quad-core within the next year:
Not all my photo collection is digital, so one of my longer term projects is to digitize my 35mm and medium format images...or at least the "best of". Because this effort takes a lot of touch labor (including sorting through images to decide what to scan), my philosophy is that if I'm going to make the effort, I'm not going to cut corners. So I favor scanning at higher resolutions so that I have the maximum of original data saved. I'll then down-sample for the application desired (print, email, web, etc).
For one early scan (of a Kodachrome slide), I actually kept track of things. Here's the statistics:
Scanned size: 17433 x 11551 (yes, that's a 2000+ MegaPixel image); 1.2GB Photoshop file (48 bit color depth)
After scanning & saving, I quit and restarted Photoshop to prevent any performance gain from buffering. It took 1:20 (one minute, twenty seconds) just to read it in from the hard drive (G5 used SATA-I).
Performing an "Auto-Level" ...a CPU intensive task...took nearly 7 minutes.
Down-sampling it to 6MP (3018 x 2000) took 1:35.
Reworking the original to "merely" a 120MB Photoshop file (8717 x 5778; = 50 MegaPixels equivalent), it then took :05 to load, :02 to AutoLevel, ~:01 to do a 180 degree rotate, ~:01 to run a sharpen filter. Even though these have a noticable pause, I consider this to be pragmatically fast enough performance, as the hardware won't generally going to impede the workflow. Obviously, even smaller (4, 6, 8, 12 MegaPixel) images can only have better response times which will perceptually approach "instant" much of the time.
My conclusion was that I considered my hardware to have been aequate both for the day (2005) as well as for the reasonably foreseeable future, which at the time I believed to mean "until digital cameras approach 50 MP", but today, I'm experimenting with HDR (High Dynamic Range) and taking multiple different exposures and stacking & combining them into a single image. Even with only a half dozen 8MP images (debateable equivalency, despite 6 * 8 = 48), the current Mac bogs down reeeeal fast. Since I'm areadly running 3.5GB RAM, it is time for more horsepower...
lots more.
Photoshop has been able to utilize 2 core processors for some time, but nothing higher until the next re-write.
And thus, why I haven't already jumped to upgrade my PowerMac to a Mac Pro...while waiting for Photoshop software to mature up, I can also gain a 'free' Mac Pro hardware bump; all I have to do is to extend my procrastination of digitizing my film
-hh