Feeding Mac Pro
Power consumption is on everyone’s minds. Apple’s 32-bit iMac set records in my tests by operating at about 85 watts, including the display. Mac Pro's power efficiency is entirely in line with other Woodcrest systems I've seen. Apple adds relatively little magic here, and I don't know how much opportunity Apple had that it didn't use. Intel's power sparing can be automatic and OS-directed, so I'm hopeful that Apple will use firmware and OS updates to push the idle power utilization down from the 220 watts I measured in my tests. That figure does not include the display.
In sleep, power draw falls to about 7 watts with Ethernet ports actively listening for administrative commands. It took the Mac Pro eval box with 4 GB of RAM only four seconds to wake from sleep, so sleep mode ought to be used liberally. Unfortunately, the idle timer used to trigger sleep is reset only by the keyboard or mouse, so background renders, compiles and the other non-interactive operations common to workstation use might cease when the user walks away. However, sleep mode can be triggered from a script, and Mac Pro will sleep and wake on a user-settable schedule. Instead of disabling sleep out of frustration, find a way to make it work for you. It matters.
Floating some points and flinging some pixels
Performance ranks rather high among things that workstation users desire in excess. Given the same CPU and core logic, Woodcrest systems from PC vendors A, B and C, running at the same clock speed, will turn in identical computing performance. The hilly playing field that Apple set up with PowerPC is now flat; on everyday benchmarks, anything can run as fast as a Mac workstation. [...]
Mac Pro can hold two or three more hard drives than users expect to find in a workstation or power desktop, and I’ve found that one of the best uses for that gravy is a RAID 0 (simple interleave) stripe. OS X Tiger, which ships with Mac Pro, makes child’s play of creating easily restorable drive images on external storage. So I created a three-drive RAID 0 set on Mac Pro and set the machine to back itself up to a parity-protected Xserve RAID volume during the wee hours. When OS X Leopard ships, that protection will be continuous and genuinely automatic. People understandably get nervous about striping without parity, but if you’re a workstation user whose disks are constantly active, the performance boost of RAID 0 for work in progress files shouldn't be disregarded as long as you balance the risk.
Apple takes a more liberal approach to thermal thresholds than its competitors do. By that, I mean that Apple does not throttle the CPUs down when they get a little warm, hot or downright incandescent. Like all Macs, when Mac Pro is running full-out with a maximum compute load, it will hold top CPU clock speed and voltage past what other vendors consider to be the thermal danger zone. Apple does this without cranking the fans up to intolerable noise levels. I made Mac Pro go loud by letting the room heat up to over 90 degrees. But in ambient temperature that’s more favorable to human existence, Mac Pro keeps itself quiet.
I ran, and am still running, a number of performance and endurance tests, but the simplest one that hits both the CPU cores and the graphics processing unit (GPU) is SPECviewperf. The savvy will point out that SPECviewperf is strictly a test of the speed at which pre-computed 3-D scenes can be displayed. However, SPECviewperf 8.1 turns in usefully varying CPU usage patterns that tend to favor the 60 to 90 percent utilization window. SPECviewperf is a single process, single threaded benchmark, so the thing to do is run multiple simultaneous instances, one per core. All I cared about was noise and power consumption, and with four SPECviewperf 8.1 processes running side-by-side, Mac Pro ate around 300 watts. The fan never got loud, and the frequency and timbre of its noise is actually pleasant and easy to block with a unidrectional ("noise reducing") microphone.