A. That really depends on whether you have one SATA 300 disk or several SATA 300 disks. The difference between the two versions is speed. The SATA 150 disk operates at 150Mbps, and the SATA 300 disk at 300Mbps. The SATA speed is the maximum speed of the controller. Both disks are far faster than a hard disk, which typically max out at 60Mbps. So, if you’re using only one disk, there’s very little difference between the two versions.
The difference is obvious when you chain multiple SATA drives into a RAID configuration. If you have four standard hard disks in a RAID 0 configuration, the array would peak at 240Mbps, which would be faster than the SATA 150 disk drive. The SATA 300 would be better in that configuration. If you have just one or two hard drives connected with a SATA disk drive, you probably won't see any difference. If you have three or more hard drives connected, the SATA 300 would allow the drives to realize their full speed.