This is more anecdotal than anything else. I have a mid 2009 MBP with 2.26ghz and 4 gb ram. I installed a Kingston HyperX 3k 240 gb SSD, and the computer was speedy although my Blackmagic read/ writes were both in the low 100s. However, it was negotiating at 1.5 and not the expected 3gb rate. Felt I was missing something with that. So, I install a Sandisk Extreme 240 gb SSD in its place. Great read/ write speeds: 194 to 263. Did the r211m firmware upgrade. Negotiating at 3gb rate. Yet, with all that, both my wife and I noticed that the Kingston ran faster than the Sandisk. To say that I am puzzled at the observation is to put it mildly. Do all these numbers make a whole lot of difference after all is said and done? By observation they don't appear to at least in my case.