I'll try to fill you in on what I have found over the past few weeks:
Download HDtach
here -- it tests random access time, sustained read, and buffered read. My results:
Avg seek: about 19ms.
Burst speed: about 72MB/s.
Sequential read: avg 22000MB/s. (900KB/s min, 30400 max)
2 disturbing results:
First of all, the seek time is higher than it should be (not insanely high, since access time=seek time+rotational latency... maxtor shows <9ms avg seek, add about 4ms rotational latency to that and you should get a score of about 13-14ms on a healthy drive).
Secondly, the graph of the sequential read speed doesnt just look like a downward hill with a few bumps. It looks like the bottom of a spiked pit of death. There are spikes everywhere, it will jump from almost 30MB/s down to 1MB/s then back up about 50 times throughout the test. A healthy drive should not have any spikes.
I am using my quantum 6.4GB drive as my "healthy" drive. It gets avg access times of between 14 and 15 ms, and this is a 5400 rpm drive! There is not a single spike in the read graph.
1 positive result:
The burst read speed is over 70MB/s, and this means that it is not an interface issue, the drive IS running at its full ATA100. (so dont blame it on the via chipset or via drivers)