The SATA I/II/III thing is mostly about connection speeds. So putting just about *any* SSD on a SATA-I link means you won't achieve anywhere near the throughput that the drive is capable of.

But it'll still outperform any mechanical drive by a wide margin, because the near-zero seek times allow SSDs to complete I/O more quickly, and thereby to complete many many more I/O operations per second than any mechanical drive.

So on a SATA-I link, which has a 1.5 gbit/sec physical layer, the drives max out at 128MBytes/sec, about the same as a mechanical drive. Except the SSD can do 10000-20000 I/O's per second, compared with perhaps 75-100 (max) on a mechanical drive.

On a SATA-II link, with a 3.0 gbit/sec physical connection, most SSDs top out around 180-240MBytes/sec, with up to 40000-50000 I/O's per second.

On a SATA-III link (6.0 gbit/sec), we finally see the upper limits of most of the current SSDs, with transfer rates up to 500MBytes/sec or so. These kind of speeds matter most for video processing, heavy swapping, and other I/O intensive loads.

But really, just stepping up (WAYYY up) to *any* SSD makes a massive difference. Beyond that it's all gravy.

Cheers