Mac Pro Overview, 2006 to 2012

With the October 2005 introduction of the 2.5 GHz Power Mac G5 Quad, Apple had introduced the most powerful PowerPC Mac ever. Whatever was to replace it had to be a real powerhouse – and the first Mac Pro certainly was.

The 2006 Mac Pro

Mac ProThe Mac Pro was the last Mac to make the transition from PowerPC to Intel technology. Like the Power Mac G5 Quad, it had two dual-core CPUs, and even the entry-level $2,199 Mac Pro outperformed that G5 Quad.

Geekbench 2 Results

  • 2.5 GHz Power Mac G5 Quad, 3197
  • 2.0 GHz Mac Pro, 3693
  • 2.66 GHz Mac Pro, 4839
  • 3.0 GHz Mac Pro, 5383

Where the Power Mac G5 had one optical drive bay, the Mac Pro had two. Where the Power Mac G5 had two hard drive bays, the Mac Pro had four. Where the Power Mac G5 had SATA Rev. 1, the Mac Pro had SATA Rev. 2. Where the Power Mac G5 tops out at 16 GB of RAM, the Mac Pro can handle 32 GB.

Both machines have four PCI Express (PCIe) slots, one of which is occupied by a video card. The big difference is that there are not a lot of PCIe cards compatible with the Power Mac G5, but there are a lot that are compatible with the Intel-based Mac Pro.

Finally, the G5 Quad tops out at Mac OS X 10.5.8 Leopard, while the 2006 Mac Pro officially supports OS X 10.6 Snow Leopard and can be hacked to run OS X 10.7 Lion.

For those looking for a powerful Snow Leopard Mac, which would mostly be because Snow Leopard was the last version of OS X to support PowerPC software such as AppleWorks and older versions of Microsoft Office and Photoshop, the quad-core 2006 Mac Pro is a powerhouse.

Intel Xeon CPUs

The Mac Pro line doesn’t use the same consumer CPUs found in other Macs. Where the Power Mac G5 and iMac G5 used the same CPU (until the Late 2005 introduction of the G5 Dual and G5 Quad), that was never true of the Mac Pro.

Xeon was Intel’s branding for its line of server CPUs, which are optimized for multiprocessing. The first Xeon shipped in 1998, based on Pentium II technology and replacing the Pentium Pro, Intel’s previous server CPU. The Pentium II Xeon was replaced by the Pentium III Xeon in 1999.

Intel dropped Pentium from the Xeon brand in 2001 with the release of Xeon CPUs based on the same NetBurst architecture as the Pentium 4. Unfortunately, the Pentium III Xeon and Pentium 4 both provided more processing power than the “Foster” Xeon CPUs.

The Xeon made a huge leap forward in 2002, introducing Hyper-Threading to Intel’s server CPU. It outperformed the Pentium III Xeon and Athlon MP to become a very popular server CPU.

Until this point, Intel’s x86 architecture was 32-bit only. AMD had defined an extended instruction set to add 64-bit support in 2000, and the first CPU to use it was the April 2003 AMD Opteron. (Intel had been pushing its Itanium  architecture, which was fully 64-bit but was not compatible with x86. It never caught on.)

CPUs using the x86-64 instruction set can run both legacy 32-bit and 64-bit operating systems and applications. (The PowerPC G5 also had full 32-bit and 64-bit support, but the Mac OS made very little use of its 64-bit capabilities.) Full 64-bit support initially gave AMD a leg up on Intel.

Intel fought back with “Paxville”, its first dual-core Xeon CPU, in October 2005 (coincidentally, the same month the last Power Mac G5 models were introduced).

Xeon CPUs Used in Mac Pros


All of this is background to the Woodcrest Xeon CPU that was used in the first Mac Pro. The chip was released in June 2006, and the Mac Pro was announced in August 2006. Woodcrest was the first server-grade CPU to use Intel’s Core architecture, boosting performance while reducing power consumption.

Mac ProThe CPU has a 4 MB Level 2 (L2) cache and a 1333 MHz front side bus (FSB) for accessing system memory. The fastest Woodcrest CPU ran at 3.0 GHz and had a power draw of just 80 Watts. (Intel’s Dempsey line of Xeons could draw 95 or even 130 Watts of power, creating a lot more heat.)

Apple ignored the slower 1.6 and 1.83 GHz Woodcrest CPUs in favor of the 2.0, 2.66, and 3.0 GHz ones.


Although Apple had released an 8-core Mac Pro in April 2007, it was based on Woodcrest architecture. It was the Early 2008 Mac Pro that moved to a new chip architecture, Harpertown. Harpertown had been released in November 2007, and the new Mac Pro arrived in February 2008. Harpertown was a quad-core CPU.

The new CPU has a 1600 MHz FSB and two 6 MB L2 caches. As with Woodcrest, Apple skipped the slower versions of Harpertown (starting at 2.0 GHz) and started at the 2.8 GHz mark, with 3.0 and 3.2 GHz options. Only the entry-level 2008 Mac Pro had one CPU; the other versions had two quad-core CPUs for a total of 8 cores.


Nehalem was the next step beyond the Penryn Core architecture used in Harpertown, and Bloomfield (a.k.a. 3500-series) was the specific version of Nehalem that Apple used in the Early 2009 Mac Pro. Bloomfield uses Core i architecture, supports up to three memory channels, and includes Turbo-Boost and Hyper-threading, which allows each core to function as though it were two separate core.

Each core has a 256 KB L2 cache, and each CPU has an 8 MB L3 cache and uses a 1600 MHz data bus (Intel replaced to older front side bus architecture with its new QuickPath interconnect). The base Mac Pro has a single 2.66 GHz quad-core CPU, while more expensive versions have two 2.26, 2.66, or 2.93 GHz quad-core CPUs. Apple added a 3.33 GHz option in December 2009.


If you thought quad-core CPUs were powerful, you should be even more impressed with Intel’s Westmere version of the Xeon, which has up to six cores per CPU. The Mid 2010 Mac Pro range included single-CPU models with a 2.8 GHz  4-core CPU, as well as 3.2 and 3.33 GHz versions. The dual-CPU Mac Pro starts out with two 2.4 GHz Westmere CPUs and has 2.66 and 2.93 GHz 6-core options.

And would you believe a 12 MB L3 cache?

The Mid 2010 Mac Pro (and the speed-bumped Mid 2012 update) was the last Mac Pro with built-in optical drives, available PCIe expansion slots, and internal hard drive bays.

Mac Pro Processing Power

From System 7, released in May 1991, through Mac OS X 10.6 Snow Leopard, Macs supported 32-bit operation. OS X 10.5 Leopard had some 64-bit support, and Snow Leopard was the transition version of OS X that supports both 32-bit and 64-bit operation. Beginning with OS X 10.7 Lion (July 2011), the Mac OS has been 64-bit only, so we’re going to ignore 32-bit benchmark results.

These multi-core results are for the new Geekbench 4, so they cannot be compared with older results in our hardware profiles. The Late 2013 Mac Pro is included for comparison. The performance of the 2.0 GHz 2006 Mac Pro is estimated based on Geekbench 2 and Geekbench 3, since Geekbench 4 results to not include it.

  • 2.0 GHz 4-core Mid 2006, 3300 est.
  • 2.66 GHz 4-core Mid 2006, 4271
  • 3.0 GHz 4-core Mid 2006, 4974
  • 2.8 GHz 4-core Early 2008, 4955

Over 1.5x 2.66 GHz Mid 2006

  • 3.0 GHz 8-core Early 2007, 7023
  • 2.66 GHz 4-core Early 2009, 7242
  • 2.8 GHz 4-core Mid 2010, 7423
  • 2.93 GHz 4-core Early 2009, 7661
  • 2.8 GHz 8-core Early 2008, 7997

Over 2x 2.66 GHz Mid 2006

  • 3.0 GHz 8-core Early 2008, 8330
  • 3.2 GHz 4-core Mid 2010, 8361
  • 3.2 GHz 8-core Early 2008, 8717
  • 2.26 GHz 8-core Early 2009, 10540
  • 2.4 GHz 8-c0re Mid 2010, 11863
  • 2.66 GHz 8-core Early 2009, 11910
  • 3.33 GHz 6-core Mid 2010, 12136
  • 3.7 GHz 4-core Late 2013, 12375

Over 3x 2.66 GHz Mid 2006

  • 2.93 GHz 8-core Early 2009, 12889
  • 2.4 GHz 12-core Mid 2012, 14829
  • 2.66 GHz 12-core Mid 2010, 16294
  • 3.5 GHz 6-core Late 2013, 16411

Over 4x 2.66 GHz Mid 2006

  • 2.93 GHz 12-core Mid 2010, 17632
  • 3.1 GHz 12-core Mid 2012, 17702
  • 3.0 GHz 8-core Late 2013, 20470

Over 5x 2.66 GHz Mid 2006

  • 2.66 GHz 12-core Late 2013, 22938

To help you see the performance tiers over time, I’ve added separators at 1.5x, 2x, 3x, 4x, and 5x the speed of the 2.66 GHz 4-core Mid 2009 Mac Pro. If you want the ultimate in Mac Pro performance for a model with expandability, the 3.1 GHz 12-core Mid 2012 is a powerhouse – but the 2.93 GHz Mid 2010 model is only 0.4% slower, so it’s no slouch. Both over over 4x the power of the 2.66 GHz 2006 Mac Pro.

Buying Advice

There are two versions of Mac OS X that need to be considered. OS X 10.6 Snow Leopard is old school, lets you run old PowerPC software via Rosetta, has a small memory and hard drive footprint, and is probably something all longtime Mac users will want on at least one Mac for compatibility with old software. A 2.66 GHz 4-core Mac Pro will be inexpensive and probably provides plenty of power for these users. Higher speeds and more cores are nice, but you’ll tend to pay a lot more for more powerful models.

If you’re really on a tight budget, you can probably save some money with the 2.0 GHz 2006 Mac Pro, but you’re also giving up 25-30% of the power of the 2.66 GHz model.

With a lot less overhead than newer versions of OS X, a first generation Mac Pro can be a great file server, print server, and music server for your network as well as a good all around production computer. (I use a 2.0 GHz Core 2 Duo Mid 2007 Mac mini and a 2.0 GHz Core 2 Duo aluminum MacBook daily. The Mini would probably score under 1300 on Geekbench 4, and the MacBook scores 1286. The 2.66 GHz 2006 Mac Pro more than triples those figures!)

The Mac OS other version you want to consider is macOS Sierra, which is the current version and can be installed on almost every Mac from 2008 forward. For the home user, something with a Geekbench score in the 7,000 to 12,000 range should provide plenty of power and expansion options. For power users, I suggest looking at the 2.8 GHz 8-core Early 2008 (7997 score) and higher.

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