HOLY SMOKES!!!!!!! Is all I can say about doing the firmware hack/upgrade on my 2009 Mac Pro. Seriously, if you're on the fence, do it. I went from a single 4 core 2.93 Ghz processor to the 6 core 3.33 Ghz Westmere processor. I found the CPU used on ebay for $125 shipped. Not only is it enormously faster. It runs about 3 degrees C cooler than the 4 core (FTW????). The upgrade was easy, painless and took less than 30 minutes. Sorry to brag guys but COULDN'T BE HAPPIER!!! Almost doubled the score!!!! See the Geekbench 3 scores below.
Xeon Nephelem W3540 4 Core:
Benchmark Summary
Integer Score 2179 9810
Floating Point Score 2513 11375
Memory Score 1946 2095
Geekbench Score 2266 8893
Xeon Westmere W3680 6 core:
Benchmark Summary
Integer Score 2939 17859
Floating Point Score 2853 19195
Memory Score 2008 2143
Geekbench Score 2718 15250
Xeon Nephelem W3540 4 Core:
Benchmark Summary
Integer Score 2179 9810
Floating Point Score 2513 11375
Memory Score 1946 2095
Geekbench Score 2266 8893
Xeon Westmere W3680 6 core:
Benchmark Summary
Integer Score 2939 17859
Floating Point Score 2853 19195
Memory Score 2008 2143
Geekbench Score 2718 15250