Looking through the past, it seems that lack of a SATA 3 controller may be causing my Intel 520 to run slower then it can.

The best computer I have currently is an Intel i5-760 with only SATA 2 ports.

At some stage in the future, I'll have to try and get a benchmark run or 2 on my intel 520 using an intel sata 3 board, see if it makes a difference, in particular to the overall endurance MB/s.