I can not switch my Mac Pro model 1,1 (2008) - 266 GHz Intel Xeon from 32 bit to 64 bit OSx? I currently have 3 GB of memory but want to upgrade to 8 GB.
Mac Pro, Mac OS X (10.6.8)
Sorry, but you can't. Only 2008 MPs and later.
The 2006/2007 Mac Pros only have 32 bit EFI and thus can't run a 64 bit kernel.There are hacks to get it to rn higher than Lion (Lion was last OS to have 32 bit kernel)
http://oemden.com/sixty-four-on-thirty-two-sfott/
The 32 bit kernel supports more than 4 GB of memory but one app.process can't use more than 4 GB
Nothing is stopping you and long overdue to put 4x2GB ($45 now).
Those 512MB FBDIMMs, time for them to go. They add heat and use energy and often run too hot really.
Throw in an SSD like XP941 256GB for the absolute best in performance.
What you have trouble doing, is booting in 64-bit mode and for processes to use more than 3.5GB each, NOT that the system can't use max RAM which is 32GB.
And with a little help from a friendly tool, you can run Mavericks or Yosemite, but not endorsed by Apple.
Hit up Amazon for "Mac Pro 667MHz FB-DIMM" and look for the $23 sets.
The recommended hacks are complex. You may find them overwhelming if you are not "handy", do not think like a Developer, or your strengths are mostly in the Creative area.
You need to know those hacks are a little hard to install and will have some day-to-day repercussions. You may be signing up for more work in the "guts" of your computer than is comfortable for you.
Dual core Intel Xeon will not switch to 64 bit OSX 10.6.8
