As everyone knows, when building a dream pc, there's always a possibility that it will be outdated as you put the case cover on. Despite being fully assembled upon arrival, the Apple Mac Pro is no different. When the Mac Pro was released in March of 2009, it boasted a 2-2.66 Quad-Core Nehalem Xeons with 6 GB of RAM, costing nearly $5000. Since then, not only has Intel released an updated version of their Xeon Processor (Westmere), but also many other components have advanced as well.
Although you can replace many of these components with their newer, faster counterparts; changing the processors out with the Westmere Xeons would at first thought, lead one to believe that it wouldn't work. Despair not: user MacEFIrom on netkas.org has found a firmware workaround to allow use of Westmere Xeons in the 2009 Mac Pro:
"Inside the EfiUpdaterApp2.efi program are a list of firmware version strings from different releases of the 2010 Mac Pro, along with the CRC32 checksum of the firmware image file. If one of the firmware version strings is modified to what the 2009 Mac Pro model is, and the CRC32 checksum is changed to match the 2010 Mac Pro firmware image, and the firmware image filename is changed to the 2009 Mac Pro firmware image filename, then all is well."
The custom installer essentially has firmware strings from the 2009 Mac Pro inserted into the 2010 Mac Pro firmware update image, thus allowing the updater to work its magic. Fortunately, this update works because the 2009 Mac Pro has very similar base system components as the 2010 Mac Pro. MacEFIrom also included a mechanism to downgrade the updated firmware to the original if any issues are encountered.
As for value, the current 2010 model (similarly equipped as the 2009 model mentioned earlier) is priced at $3,499 on Apple.com, and is currently not recommended for purchase by MacRumors.com, as the 2010 model is due for a refresh. To update the 2009 model, one would not only have to update the firmware, but also purchase additional processors. Newegg is currently listing the 2.66 Six-Core Processor for $1019.99 each. Another option is that some Nehalem processors support DDR3-1333, so with matching RAM, and this firmware update, it would be possible to run the RAM at 1333 MHz, according to arstechnica.com. Also mentioned in this article, is that if the OS X installation becomes unusable, the 2009 Mac Pro restore discs won't work, the 2010 Mac Pro restore discs will be needed.