"2006 Mac Pro (1,1) w/Dual 2GHz Xeon 5130 (Dual Cores)
Upgraded to Dual 2.33GHz Xeon E5345 (Quad Cores)
I was a bit apprehensive about doing this after reading all the upgrade reports as well as the sites people had made showing the upgrade method they used.
I got the E5345 Quad cores off ebay for $225 total shipped (May 2011 cost). They are "E"'s but have no idea if that means Engineering Samples or not. (Here's a wiki page on Clovertown (53xx) E and X series-Mike) Thought of getting 5365's (3 GHz) but they were $400 or so each and because of the reports, didn't want to waste $800 if it didn't work. Now wish I had.
Everywhere I went to get instructions on how to do the swap made it seem MUCH MUCH more difficult than it actually was. The heat sink cover was hard to get off until I realized that you need to pull out the bottom right corner then it rotates, CCW easily, to remove. (The cover to the left of the memory bay (the CPU cover) rotates, pivots, on the upper left corner of the cover but first you must pull out, carefully, the lower right corner to clear the memory cage as it is rotated.)
The front fan has a screw on the top-right-back that secures it to the motherboard, and the fan does not pull out very easily, maybe because it was stuck after 4+ years since being built.
Removing the heat sinks, installing the "new" processors and reassembly was a non event. The whole swap took maybe 30 minutes at the most from power down to pushing the power button to start it up. No issues with the screws
Powered on, and was overjoyed to hear the bong. About this Mac showed "2 x 2.33 (unknown)" that was corrected by installing AboutThisMac (from Jul 2009 report which also has links to Video and early Mac Pro CPU Upgrade guide.) - it now shows: "2 x Intel® Xeon® CPU E5345@2.33GHz" Reported to run between 84° - 97° unloaded and 122° - 129° (just under 54°C) loaded 100%
Has a flashed PC ATI Radeon HD 5870 (ebay about $350 3 months ago)
Power Fractal = 61755Mflops (after upgrade). Have no clue how these numbers compare (to original cpus) as I didn't run them before the swap (forgot).
Your site has saved my bacon many times over the years.