I'm not sure how to address your problem specifically, but I did quite a bit of research on the subject and the SATA people say that there is no difference in the cables used for SATA spec. They wanted the SATA II and III devices to be backwards compatible with existing cables so that's what they did. You will notice some companies out there selling SATA III cables but in fact there is no difference.
If your Mobo has only 2 SATA III ports then you probably have 5 or six SATA II ports and 2 additional SATA III ports. That means that any drives plugged into the SATA II ports will operate at SATA II speed (3.0 Mbps) even if they are SATA III drives. The difference is not in the cables, it's in the physical hardware (Chipset) built onto the Mobo and the Drives. In order to get your SATA III drives to operate in SATA III mode they have to be plugged into a SATA III Port.
You can't change the state of the SATA ports to SATA II or SATA III in BIOS. Again, Physical hardware issue.
AHCI (not AHCL) refers to the command set used to interface with the drives. the choices are IDE, AHCI or RAID. You should use AHCI (or RAID if you are creating a RAID set).
Please provide system specs. so that we can give you more specific help on getting your SATA III drives operating in SATA III. It may not be advisable depending on how your SATA III controller is implemented. Besides, the actual difference in performance is probably not that noticable.
As far as what test to use to report the speed of the SSD, well I can't help you much there. The actual speed that you see is somewhat subjective any way because it depends on what your system is doing. Check out some of the articles on this page for more info. http://www.tomshardware.com/reviews/Storage,5/Internal-...