In addition, each Nehalem processor has an integrated memory controller, which obviates the need for a separate I/O chip; according to Apple, that gives the new Mac Pro much faster access to memory data, reducing latency by up to 40%.
All of this allows for some interesting internal magic, complete with hot-rodding code names. Hyper-Threading manages two computing threads running simultaneously on a single core. Turbo Boost overclocks a single core and turns off the others when an application accesses only one core. The QuickPath Interconnect system ties together the hard drives, I/O and two processors (in the high-end model) much more efficiently than the previous model's dual independent front-side buses.
About that video card...
The standard video card, the Nvidia GT 120 with 512MB of RAM, is a competent option for everyday work, though it compares poorly in benchmarks against the previous generation of Mac Pros, which came with an Nvidia GeForce 8800 GT. As a result, for professionals and most other power users, the $200 upsell of the ATI Radeon HD 4870, also with 512MB of RAM, is worth the money.
In a Call of Duty 4 time demo, our test machine delivered more than double the frame rate when moving from the GT 120 to the Radeon HD 4870. In fact, the Mac Pro with the GT 120 didn't even match published frame-rate numbers for an iMac with an 8800 GS graphics chip. (The 8800 GS is related to the GT.) Swapping in the Radeon HD 4870, though, made the Mac Pro the handy winner.
In other benchmarks, the review unit's quad-core 2.66-GHz racked up a Geekbench 2.1 score of 8350, an Xbench score of 214, and a Cinebench R10 multicore score of 14857. These numbers place this model squarely in line with the previous generation running two 2.8-GHz CPUs. This year's Mac Pro might not bury the older generation, which is selling at a discount now, but the Nehalem-based new Mac Pros look like they'll grow the gap soon. More about that later.
32GB of RAM will cost you
Looking to add RAM? The more the better, of course. Mac OS X, even the relatively mature Leopard version, loves RAM. But maxing out the Mac Pro's RAM (to 8GB on the quad-core model and 32GB on the octo-core) costs a premium if purchased through Apple. In the most extreme instance, 32GB of RAM configured from Apple costs $6,100, while the same RAM from a major Mac reseller is a third less.
Whatever amount you end up with, though, it's best to configure it in sets of threes, rather than in pairs. Since there are three memory channels per Nehalem processor, this allows saturation of all three for the best performance.
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