Mac Pro

The Mac Pro is a workstation computer manufactured by Apple Inc. The machines are based on Xeon microprocessors, but are similar to the Power Mac G5 they replaced in terms of outward appearance and expansion capabilities. They are currently one of three desktop computers in the current Macintosh lineup. The Mac Pro is currently the fastest computer that Apple has to offer.
The Mac Pro was formally announced on August 7, 2006 at WWDC.[1] Along with the Mac Pro, a new Xeon-based Xserve was also announced, completing Apple's transition from the PowerPC to x86 architecture. On January 8, 2008 Apple unveiled the first 3.2 GHz, dual quad-core Intel Xeon (Harpertown 45 nm) -based Mac Pro.[2] The current Mac Pro was unveiled on March 3, 2009, featuring the new Intel Xeon processors based on the Nehalem micro-architecture as well as a lower entry price.

Overview
An Intel-based replacement for the Power Mac G5 had long been expected prior to the release of the Mac Pro. The iMac, Mac Mini, MacBook and MacBook Pro had moved to an Intel-based architecture starting in January 2006, leaving the Power Mac G5 as the only machine in the Mac lineup still based on the PowerPC. Speculation about the G5's eventual replacement was common. Rumors initially expected the machine to differ physically from the existing G5 and considered a number of different possible internal configurations based on different chipsets. But the coincidence of Intel releasing a new Core 2-based Xeon workstation platform just prior to the 2006 Worldwide Developers Conference (WWDC) made it fairly obvious that the resulting machine would be based on it. Even the naming was "obvious"; Apple had dropped the term "Power" from the other machines in their lineup, and started using "Pro" on their higher-end laptop offerings. As such, the name "Mac Pro" was widely used before the machine was announced.[3]
The Mac Pro is a high-end computer, similar to higher end Unix workstations from vendors such as Sun Microsystems. Although the high-end technical market has not traditionally been an area of strength for Apple, the company has been positioning itself as a leader in non-linear digital editing for high-definition video,[4] which demands storage and memory far in excess of a general desktop machine. Additionally, the codecs used in these applications are generally processor intensive and highly threadable, speeding up almost linearly with additional processor cores. Apple's previous machine aimed at this market, the Power Mac G5, had up to two dual-core processors, but lacked the storage expansion capabilities of the newer design. In order to serve this market, Apple sells a variety of standardized bundles combining a Mac Pro with fairly high-end components; for instance, all available setups can support the 30" Cinema Display.
In general, the Mac Pro has been well received in the press.[5] The combination of high performance, reasonable expandability, very quiet operation and superb mechanical design makes it routinely appear as the comparison system against which other systems are measured. The Xeon platform is, however, Intel's "high end" system and not aimed at more general purpose use. Nevertheless, current-generation Xeons are priced competitively with their high-end desktop platforms, allowing Apple to sell a very powerful system at price points that are considered quite competitive, even by reviewers who do not normally review Apple systems.[6]
Original marketing materials for the Mac Pro generally referred to the middle-of-the-line model with 2 × dual-core 2.66 GHz processors. Previously, Apple featured the base model with the words "starting at" or "from" when describing the pricing, but the online Apple Store listed the "Mac Pro at $2499", the price for the mid-range model. The base model could be configured at US$2299, much more comparable with the former base-model dual-core G5 at US$1999, although offering considerably more processing power. Post revision, the default configurations for the Mac Pro includes one quad-core Xeon 3500 at 2.66 GHz or two quad-core Xeon 5500s at 2.26 GHz each.
The Mac Pro is the only machine in Apple's lineup with industry standard PCI express (PCIe) slots for graphics cards and other expansion cards.

Description

Processors
The current Mac Pro uses either one or two Xeon 5500 "Gainestown" or Xeon 3500 "Bloomfield" (both based on the Intel Nehalem microarchitecture) 64-bit CPUs for a total of four or eight processor cores. Each CPU has an 8 MB on-chip L3 cache shared among its processor cores.[9] Because the most recent revision is based on the Nehalem microarchitecture, the old Front Side Bus technology has been replaced by the Intel QuickPath Interconnect interface. Both of these processors are capable of Intel's Turbo Boost technology (similar to Intel's SpeedStep technology), which dynamically boosts the clock rate of a core in intervals of 133 MHz if the CPU temperature is below average conditions.
Memory
The original Mac Pro's main memory used 667 MHz DDR2 ECC FB-DIMMs; the early 2008 model used 800 MHz ECC DDR2 FB-DIMMS, the current Mac Pro uses 1066 MHz DDR3 ECC DIMMs. In the original and 2008 models, these modules are installed in pairs, one each on two riser cards. The cards have 4 DIMM slots each, allowing a total of 32 GB of memory (8 x 4 GB) to be installed [10]. Notably, due to its FB-DIMM architecture, installing more RAM in the Mac Pro will improve its memory bandwidth, but may also increase its memory latency.[11] With a simple install of a single FB-DIMM the peak bandwidth is 8 GB/s, but this can increase to 16 GB/s by installing two FB-DIMMs, one on each of the two buses, which is the default configuration from Apple. While electrically the FB-DIMMs are standard, Apple requests that users use larger-than-normal heatsinks on the memory modules that they install. Problems have been reported by users who have used third party RAM that had normal sized FB-DIMM heatsinks.[12](see notes below).
Hard drives
The Mac Pro has room for four internal standard 3.5" hard drives, in sizes up to the current maximum available running at 7200-rpm or 15,000-rpm, each with its own SATA-300 port. With the addition of a SAS capable RAID card, SAS drives can be used with the SATA ports. The hard drives are mounted on individual trays (also known as 'sleds'), provided with the machine, by captive thumbscrews similar to the one used for the PCIe slots. There are no cables to be attached, the SATA and power connectors are firmly attached to the case, and the drive is connected to them simply by pushing it in. The case lock on the back of the machine locks the trays into position. The Mac Pro now offers an optional hardware RAID card.[13] Two optical drive bays are available, each with a SATA-300 port and an ATA-100 port. Many optical drives still use the older ATA ports, including those currently being shipped with the machines.
The Mac Pro has 1 P-ATA port (for up to two P-ATA devices) and a total of 6 SATA ports, 4 integrated in to the drive bays, and two internal SATA ports that are not connected to drive bays. These extra SATA ports can be put into service through the use of after-market extender cables, for use with internal Optical drives, or to provide eSATA ports with the use of an eSATA bulkhead connector.[14]
Overall, a built to order Mac Pro can be configured with up to 4 TB of storage (four 1TB disks) but can support any four SATA hard drives so 8TB is possible with aftermarket 2TB disks.
Expansion cards
For internal expansion the current Mac Pro has four PCI Express (PCIe) 2.0 expansion slots. The 2008 model had two PCI Express (PCIe) 2.0 expansion slots and two PCI Express 1.1 slots, providing them with up to 300 W of power in total. The first slot is double wide and intended to hold the main video card, arranged with an empty area the width of a normal card beside it in order to leave room for the large coolers modern cards often use. In most machines, one slot would be blocked by the cooler. Instead of the tiny screws typically used to fasten the cards to the case, in the Mac Pro a single "bar" holds the cards in place, which is itself held in place by two "captive" thumbscrews that can be loosened by hand without tools and will not fall out of the case.
The PCIe slots can be configured individually to give more bandwidth to devices that require it, with a total of 40 "lanes", or 13 GB/s total throughput. When running Mac OS X, the Mac Pro currently does not support SLI or ATI CrossFire, limiting its ability to use the latest "high-end gaming" video card products; however, individuals have reported success with both CrossFire and SLI installations when running Windows XP.[15] SLI/CrossFire is largely a function of software.
The bandwidth allocation of the PCIe slots can be configured via the Expansion Slot Utility included with Mac OS X only on the August 2006 Mac Pro. The Mac Pro (Early 2008) has its slots hardwired as follows.
External connectivity
For external connectivity, the Mac Pro includes five USB 2.0 and four FireWire ports, two of the latter being FireWire 800. Networking is supported with two built-in Gigabit Ethernet ports, while 802.11 a/b/g/draft-n[16] Wi-Fi is supported via an optional AirPort Extreme card. Bluetooth is now standard.
Digital (TOSlink optical) audio and analog 1/8" stereo mini jacks for sound in and out are included, the latter available on both the front and back of the case.
Unlike other Mac products, the Mac Pro does not include an infrared receiver (required to use the Apple Remote). Beginning with Mac OS X 10.5 Leopard, Front Row can be accessed on the Mac Pro (and other Macs) using the ⌘-Esc key combination.
Case
The exterior of the aluminum case is very similar to that of the Power Mac G5, with the exception of an additional optical drive bay, and a new arrangement of I/O ports on both the front and the back. The case can be opened by operating a single lever on the back, which unlocks one of the two sides of the machine, as well as the drive bays. All of the expansion slots for memory, PCIe cards and drives can be accessed with the one panel removed, and require no tools for installation.
The Xeon processors generate much less heat than the previous dual-core G5s, so the size of the internal cooling devices has been reduced significantly. This allowed the interior to be re-arranged, leaving more room at the top of the case and thereby allowing the drives to double in number. Less heat also means less air to move out of the case for cooling during normal operations; the Mac Pro is very quiet in normal operation, quieter than the already-quiet Power Mac G5,[17][18] and proved difficult to measure using common decibel meters.[19]

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