Benchmarking accuracy?

I have 2 SATA drives in my (aging) HP M9177C - st31000340as and hdt725032vla380 - both with similar(ish) performance specs.

The Benchmark function for the Hitachi is around 3 MB/sec whereas the Seagate benchmark results show 60+ MB/sec !?!?

Why such a disparity? Is Defraggler's benchmarking reliable?

on my hitachi also 3 mb/sec :-))

the "calculation of drive performance" makes 2 gib jumps with my Hitachi ...

1.) 20 to 40 %

and

2.) 59 to 80 %

perhaps missing something of hitachi that has the seagate?

with you too?