Performance in Intel IOMeter

Sequential Read/Write Pattern

This pattern performs sequential reading and writing in blocks of an increasing size in order to find the maximum speed of each HDD as well as the dependence of speed on the data block size.

As we noted in a previous report, the updated electronics of the Deskstar T7K250 works much better with data blocks smaller than 8KB at sequential reading and writing. The cluster size in NTFS is 4KB by default, so it’s a good thing for Hitachi that its HDDs achieve their maximum speed at such data blocks. The lower read speed of the HDT722525DLA380 in comparison with its ATA mate (and the difference in speed between the two versions of the 7K250) is due to the degradation of the characteristics of the HDDs we noted in our earlier reports. Another sample we tested later on had a max read speed like that of the HDT722525DLAT80, but was anyway slower on data blocks smaller than 4KB, probably due to the Native Command Queuing overhead.

Maxtor’s DiamondMax 10 drives of the first and second version process small data blocks even better. They reach their max speed as soon as 2KB blocks. Strangely enough, the latest DiamondMax 10 generation has a considerably higher maximum speed, but its speed of processing small data blocks is as low as that of the previous generation (DiamondMax 9), and the ATA version is even worse than that.

The two Samsung products have odd sequential read results. They are considerably slower than most of the above-discussed models at reading in small data blocks, and they show a very strange correlation between the read speed and the data block size. Besides, having a very good speed at reading, the ATA model suddenly slows down at writing but improves its results in later tests, surpassing the SP2504C in writing as well. These symptoms suggest an after-write check that we found in Maxtor’s HDDs are few years ago.

The ATA-interfaced Seagate Barracuda 7200.8 acted up as well. It refused to accelerate on data blocks larger than 2KB at sequential reading although it did show a read speed of 66MB/s like the version with a Serial ATA interface. The next generation (Barracuda 7200.9) progressed greatly in terms of its speed with small data blocks but did not match the fantastic results of the Maxtors. By the way, the enlarged 16MB buffer didn’t affect the results of the ST3250624A/AS in this test.

Western Digital doesn’t produce any surprises for us. Four HDDs have identical and quite high speeds of reading while the updated electronics of the WD2500JS/KS is somewhat slower. Since the WD2500JS has increased-density platters, it has a higher top speed which is achieved on 8KB data blocks. All the six models are equally successful at writing.