I have an old Mac Pro with the following serial number G87391T6UPZ. Can I upgrade this computer to 10.9 or 10.10?

I can't seem to find an official website that tells me 'yes' or 'no'. It runs on a 2.66 Ghz Quad-Core Intel Xeon. There was a website that mentioned early 2008 and up can upgrade. But not sure when this was made...


It says it is MacPro 1,1


4 Answers 4


There is only one available 2.66 GHZ Quad-Core Intel Xeon Mac Pro, which actually is powered by two 2.66 GHz dual core Intel Xeon 5150 processors: MacPro1,1

The maximum OS is Mac OS X 10.7.5, if the RAM was upgraded to at least 2 GB.


It is possible to upgraded a MacPro1,1 to Yosemite, but it is a bit of work and not perfect. You will have to add a third-party new boot loader software, and most likely upgrade the graphics card. A number of OS X -- mostly minor -- features will not be available.

This is almost like building a Hackintosh, but Apple will not consider you as violating OS X's license.

For full details see: http://forums.macrumors.com/showthread.php?t=1740775

Remember, the setup could break when ever you do a minor system update. So you would want to carefully research an upgrade from 10.10.1 to 10.10.2


Your "G5" is actually a Mac Pro, judging from your serial number (VERY useful info, thanks) according to appleserialnumberinfo.com, link here.

Assuming the info is correct, yes you can upgrade to the current OS X, Yosemite. The best way to check is to go to About This Mac from the Apple menu, and select the More Info option. In Hardware Overview you will find a model number. If yours is MacPro 3,1 then it will support Yosemite.

Bear in mind you'll want upwards of 4GB RAM (8GB or more, ideally) if you want to get the most out of both the hardware and OS.

Edit - As klanomath points out, it looks like your Mac Pro is more likely to be a Mac Pro 1,1 - given the CPU configuration - and so your OS ceiling will be 10.7.5

  • It can't be a MacPro3,1 because that one was delivered with at least Mac OS X 10.5.6
    – klanomath
    Commented Mar 23, 2015 at 21:42
  • Looks like you missed my edit ;-) Commented Mar 23, 2015 at 21:42
  • i saw the edit hint (how is it called in english?) while writing... ;-)
    – klanomath
    Commented Mar 23, 2015 at 21:44
  • "Edit hint" is just fine ;-) Appleserialnumberinfo.com's declaration of "maximum OS - current" does suggest their database is out of date by 4 years - AND they have the cheek to charge users for searching their database more than twice in 24 hours :-/ Commented Mar 23, 2015 at 21:53
  • There's an Apple Website for identifying models from serial numbers Check Your Service and Support Coverage. It was unhelpful returning OBS, MacPro. There's also EveryMac.com's Ultimate Mac Lookup, which gets you close 1 of 4 models, where the CPU speed gives it away.
    – user90735
    Commented Mar 23, 2015 at 23:35

I don't have sufficient to add comment so I'll add an answer: "OBS, Mac Pro" on Apple's web site means it's the original Mac Pro released in 2006, this is the official name used by AppleCare and GSX.

As such, the officially supported OS X version for the Mac Pro is 10.7.5.

Unofficially, this Mac Pro can be hacked to run later OS X given a proper graphic card upgrade.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .