"Just like your last report (May 25th, 2011 news) on this subject - I upgraded a Dual 2Ghz (Xeon 5130, dual-cores) Mac Pro 1.1 with a pair of Xeon 5345's (2.33Ghz, Quad-Cores) I bought off ebay for 200 for the pair (I'm in the UK.)

Install took about 40 minutes and the unit powered up just fine. I also bought an additional 8 Gig ram from ebay (it now has 13 Gig so I'm aiming to get it up to 16GB in time) and have ordered a Radeon 5770. Also thinking of a small SSD to use for Windows as I have some Flight sim games I'd like to run on it under bootcamp.

I'm a fan of Geekbench and ran the free version on the original 2Ghz configured unit (Mac pro on the machine list of the page). I've since purchased Geekbench and have now run it on the upgraded Machine in both 32 & 64bit modes (Mac Pro 1.1 on the list) and compared it against my 2009 8-core 2.26GHz Mac Pro with 32 Gig ram in both 32 & 64 bit mode.
(FYI: Mac Pro 1,1 (2006) and 2,1 (2007) are EFI32 models and not able to boot to 64-bit Snow Leopard kernel as is.)
My Macbook Air and Core i7-2620M 13" MacBook Pro are there too. You can see the 5345's make a huge difference and bring it surprisingly close to the Nehalem 09 Mac pro. http://browse.geekbench.ca/user/MCal27/geekbench2
Hope it's of Interest & keep up the good work.
-Alan B."

Thanks Alan. Here's links to a few other previous Mac Pro CPU upgrade reports this year. (Some linked on Macs Mods/Upgrades page.)

• 2006 Mac Pro CPU Upgrade ($225 for Pair of E5345 Quad-Cores) (May 25th, 2011)
• 2010 Mac Pro CPU Upgrade (2.8GHz 4-core to 3.2GHz 6-Core) (April 20th, 2011)
• Water Cooled 2006 Mac Pro w/3.3GHz (OC'd 2.66's) Quad-Core CPUs (March 23, 2011)
• 3 More Mac Pro CPU Upgrade reports (w/Software OC report) (Mar 1, 2011)
• 2006 Mac Pro Quad-Core CPU Upgrade report (5350's OC'd to 3.3GHz) (Jan 13th, 2011)

• (Forbes) Why Steve Jobs' keynotes matter (Fortune)
• Mac Security Threats: How Vulnerable Is Apple? (Time)

• Troubleshooting Home Sharing
• Cannot send audio from iMovie or GarageBand via HDMI with the Apple Digital AV Adapter
• iMovie for iOS: What does a yellow triangle in my timeline mean?
• Where are my iTunes files located?
• Apple Web Server notifications