2.66 Quad Core vs 2.93 Quad Core Bragging rights only, does not show real world performance difference (Courtesy OWC): CINEBENCH 14251 15800 10.86941267279489% GEEKBENCH 9390 10236 9.00958466453674% Real World Single Thread Difference: 3x2GB Sticks Total Ram 6GB 28.78 27.28 5.211952744961779% 4x2GB Sticks Total Ram 8GB 28.82 27.66 4.02498265093685% Real World Multi Thread Difference: 3x2GB Sticks Total Ram 6GB 177 165 6.779661016949152% 4x2GB Sticks Total Ram 8GB 177 163 7.909604519774012% Recent BareFeats Benchmarks: GRAPH LEGEND m2.9 4c = 4-core 2009 Mac Pro 2.93GHz with 12G of RAM and Radeon HD 4870 m2.7 4c = 4-core 2009 Mac Pro 2.66GHz with 6G of RAM and Geforce 120 GT 7.344632768361582% This percentage gain is misleading because if the 2.66 were equally equiped with 12GB Ram the percentage gain of the 2.93 over the 2.66 would now only be 6.395348837209303% in this multi threaded test. 0% Difference 0% Difference Our Testing: In real world use it is impossible to detect a performance difference between the 2.66 and 2.93. And I need to emphasize the word impossible. Five of us used both configurations for an hour each and not a single one of us could tell the difference. Your money is better spent elsewhere. What can you buy with the extra $500? Three 1TB WD Blacks (you can use the stock 640GB Blue for TM) plus add 6GB Ram and have $75 in extra change. $500 off a ACD. A SSD for $300-360 and the 4870 upgrade with it. Once we jumped on a 2.66 with SSD we could feel a dramatic performance difference. The difference is very significant and not minor like the processors. In regard to the VelociRaptor's I would stay away from them for the same insignificant speed bump difference as the processors. Here is a quote from a Raptor user: Not a quantum leap over a 32M cache 7200k Pros: The fastest consumer desktop SATA hard drive money can buy. I was expecting a bit more speed, however, all in all this is a pretty good drive. Runs very cool, cooler than my 750GB caviar black I use now as a storage drive since I got the raptor. I also think its pretty quiet for the most part as I cannot hear it over my case fans, which are of medium loudness. Cons: To me 230$ is a bit hard to swallow for the incremental performance over a fast, modern 7200K 32M drive. I gave this 4 starts simply because of its price/performance. Here are some quick results using HD Tune 2.55 vs. my WD 750GB WD7501AALS caviar black. Average Transfer rate: VelociRaptor - 101.4 MB/s 750GB Caviar Black - 90.5 MB/s Burst Rate: VelociRaptor - 182.2 MB/s 750GB Caviar Black - 143.1 MB/s Access Time: VelociRaptor - 7.0ms 750GB Caviar Black - 11.1ms Modern 32MB cached 7200k drives like a WD Caviar Black series are not too far behind the velociraptor in benchmarked speed and you will be hard pressed to notice a real world difference. Other Thoughts: Price is kinda steep for marginal speed increase over a 32MB cached caviar black. Makes you want to think about shelling out some more $$ and just take the SSD plunge. A newer SSD like the new OCZ Vertex or even Intel's SSDs wipe the floor with a conventional HD like a VelociRaptor. In my humble opinion, unless you have money to burn and don't want to get an SSD, pass on a velociraptor and get a large capacity 32MB cached Caviar Black as you will notice zero real world performance difference, save a lot of money and have much greater capacity. Again the VelociRaptor is a great fast SATA drive, but after my experience, when the rubber meets the road, this drive is not at all worth the price premium over a fast 7200k drive. If extreme storage speed is what your after, especially a drive that will serve as a boot drive or gaming drive, nothing short of a new high performance SSD will satisfy you. Note: To make matters worse, the 750GB Black that he used in his test is the worst performer of the blacks. The 500GB and 640GB are faster, and the 1TB the fastest. In other words, the VelociRaptor is even less appealing when pitted against one of the "better" WD Blacks. Remember all of this is just our opinion and we would love to hear feedback from other users.