Geometry is irrelevant to the quoted maximum, as it is a maximum. All your long explanation above says is that the drives effective data rate is less than the max media rate, where as quoted below you say the exact opposite. Out of the case, the best you could expect is less than half of SATA 2, and less than a quarter of SATA 3. The media rate may approach the maximum where geometry is favorable , and be less on other parts of the disk, but that doesn't change the fact that you can't effectively max out SATA2 or SATA 3 interfaces as moving data to/from the platters will be < the max media rate. sustained disk data transfer < max media rate (1.5Gb/s) < SATA 2 (3.0Gb/s) < SATA 3 (6.0Gb/s) Not close at all. I concur with sanjay. I'm interested in how fast my data gets on the disk and off it, not how fast it gets to/from the controller cache since it is usually buffered by system memory first, which is just as volatile as controller cache.