Now let’s take a look at the performance of Promise FastTRak TX4300 controller during sequential writing. The data transfer rates shown by the controller in this test for different data block sizes are given in the table below:

Now let’s look at the dependence graphs:

Only the single hard disk drive and RAID 0 of two HDDs performed impeccably here. The graphics for RAID 0 arrays of 3 and 4 HDDs coincide with that for RAID 0 of 2 HDDs, and the mirrored RADI1 and RAID 10 arrays fall behind a single hard drive in all test modes.

To tell the truth, this is a pretty unusual picture. It looks more like the result of certain optimizations for write requests processing introduced in the controller driver. In our purely synthetic pattern the optimizations evidently provided a negative result.