The power of hdparm
This shows the power of a well set hard disk controller:
BEFORE:
johnny:~# hdparm -tT /dev/hda
/dev/hda:
Timing buffer-cache reads: 128 MB in 0.58 seconds =220.69 MB/sec
Timing buffered disk reads: 64 MB in 8.89 seconds = 7.20 MB/sec
AFTER:
/dev/hda:
Timing buffer-cache reads: 128 MB in 0.60 seconds =212.66 MB/sec
Timing buffered disk reads: 64 MB in 1.57 seconds = 40.72 MB/sec
PS: The second test was made when the machine was under production. So the benchmark is underrated.