Also remember that the speed of which the controller operates matters as well. For example, my boards JMicron controller (raid controller) maxes out at about 110mb/s whereas the standard controller on the board maxes out at 170mb/s. If I have my SSD hooked to the JMicron, then it read/writes at 110mb/s. If I have it hooked to the standard controllers SATA ports, then it operates at 170mb/s.
Even some SATA II SSD's advertise read/write times of 200mb/s+, but depending on your motherboard, it may never reach it's potential. It's called a bottleneck.
My SSD is a SATA III and rates at 500mb/s but like I previously said, my SATA II controller maxes out at 170mb/s. So right now I'm trying to find a good excuse to drop another $300 on a board so I can reach that 500mb/s potential!
Hope that helps.
EDIT P.S. Also, you can't just change your BIOS to AHCI even if your BIOS allowed it as the system would just blue screen at boot time and vice versa if you change from AHCI to IDE. You have to choose that before you install windows. So remember to change that setting before installing Windows on your next motherboard or system.
Edited by Ferrari, 15 March 2012 - 09:56 PM.