Mac Pro: The perfect workstation

With more than double the memory throughput of an eight-core, 3GHz Xserve, the massively parallel Nehalem-based Mac Pro is built to rock your world

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Because so many workstation workloads operate under just this model, with several threads pounding on a shared data set, STREAM is an exceptional predictor of overall workstation performance. The STREAM results were echoed in my 3-D rendering, AVCHD (high-definition H.264 video) stream transcoding, and string search and sort tests. In all of these tests, the 2.93GHz Nehalem Mac Pro outperformed the eight-core Xserve by at least 50 percent. Straight-ahead integer and floating point scores were comparable to those of other Intel Core 2 systems at similar clock speeds, which is to be expected considering the microarchitecture is largely unchanged. However, the Nehalem Mac Pro's aggressive power management let it handle the same workload with less power.

Let it Snow
The best of the Nehalem Mac Pro is yet to come. Like the iPhone, this is a system that will improve with time at no cost to its owners. Snow Leopard just lights it up in ways that I can't describe (I'm under non-disclosure, but June's not that far away). Even pre-Snow Leopard, turning Intel's version 11 compilers loose on your existing code will produce some surprising results. Mac developers should consider a two-socket Mac Pro a must-purchase, and parallelization of their applications a top priority.

The Mac Pro is available in a variety of configurations. As I see it, the sweet spot is the custom build with two 2.66GHz CPUs, 12GB of RAM, and the hardware RAID controller at $5,699. With Nehalem's bus opened up, disk I/O performance surfaces as a severe bottleneck. A compile of the SPEC CPU2006 benchmark suite (using eight processes) took twice as long on the new Mac Pro without RAID as it did on old Xserve with RAID.

The strange not-power-of-two memory configuration relates to Nehalem's triple-channel memory controller. Its best performance is derived from attaching three DDR3 DIMMs to each processor. This leaves two DIMM sockets vacant, and there's some controversy over the performance impact of filling them. I created a 14GB configuration by moving two DIMMs from the 2.26GHz test machine to the 2.93GHz unit. I reran the eight-process STREAM tests and got the same results, but your mileage could vary.

Either way, I don't see it as an issue. RAM is upgradable, more easily in the Nehalem Mac Pro than in any other PC, and as higher-density DDR3 DIMMs become available, you can build your own perfect workstation. You can't get a better start toward that end than with the Mac Pro.




Apple Mac Pro ("Nehalem")

$2,499 for base model with one 2.66GHz quad-core Intel Xeon 3500 Series CPU, 3GB 1066MHz DDR3 RAM, 640GB hard drive, 18X SuperDrive DVD burner, Nvidia GeForce GT120 graphics card with 512MB GDDR3 memory; $3,299 for two 2.26GHz Xeon 5500 Series CPUs and 6GB of RAM; $6,799 as reviewed with two 2.93GHz quad-core Xeon 5570 CPUs, 12GB DDR3 RAM, AMD ATI Radeon HD 4870 with 512MB GDDR5 RAM, two 1TB Serial ATA hard drives.

Mac OS X 10.5.6 Leopard (included); dual-boot Windows XP and Windows Vista with Boot Camp; other EFI (Extensible Firmware Interface)-compliant x86 operating systems depending on drivers.

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