[See also my MacBook Pro Experience Report]
I’m sticking with my assessments in my August 8 entry, but barefeats.com tests show that the Apple MacPro 2.66 GHz is so fast that it is in spitting range of the PowerMac G5 Quad with Photoshop (see also the barefeats.com Armchair Analysis). This is true even though the MacPro has to run Photoshop in emulated mode. A 3 GHz model will close that gap by up to 13% (3.0 vs 2.66 GHz)—but the real-world improvement remains to be seen, since it depends on more than just clock speed. But $800 is better invested in memory than a piddly 13% clock-speed increase.
So for users who are casual or moderate users of Photoshop, the MacPro might be a reasonable investment now, provided that the extremely expensive memory is palatable. If you need 8GB or 16GB, it’s going to hurt. Were I starting with an all-new machine, I’d go with the MacPro and live with the emulated performance for a time.
On the other hand, fully loaded PowerMac Quad G5 machines might quickly become bargains. If someone offered me $3500 for my Quad with its 8GB ECC memory (6 months old), I’d quickly accept the offer. But selling it for less than that to get a performance decrease with Photoshop (which I personally could live with) makes no sense at all, so I’m just going to keep the G5 Quad for another 6-9 months—still the best Mac I’ve ever used.
It also appears that the MacPro 2.66 GHz offers up to 50% performance increases when using Universal Binary applications that make use of all the cores. Whether this is also true of single-threaded applications will become clear within the next week or so. I will also be posting test results for my Integrity Checker program, courtesy of barefeats.com. Integrity Checker makes the most efficient use of a quad-core (or any number of cores) of any program I’ve yet come across. Well, I’m an expert software developer, so what do you expect?