Performance in IOMark

We use our internal IOMark tool for low-level tests. Let’s check out the sequential read speed of the drives first.

• Data-transfer graph for Western Digital Scorpio Blue, 500GB
• Data-transfer graph for Hitachi Travelstar 7K200, 200GB
• Data-transfer graph for Seagate Momentus 7200.2, 200GB
• Data-transfer graph for Seagate Momentus 7200.3, 320GB
• Data-transfer graph for Western Digital Scorpio Black, 320GB
• Data-transfer graph for Seagate Barracuda 7200.11, 320GB
• Data-transfer graph for Western Digital Caviar Blue, 320GB

Now we can compare the HDDs by the read speed at the beginning and end of the partitions created on them.

It is easy to see the progress the models with 160GB platters have made over the previous generation. The recording density being 1.5 times as high as in the previous-generation HDDs, their sequential read speed is about 25% higher. Interestingly, the Seagate 7200.3 is considerably faster than the Western Digital Scorpio Black at both the beginning and end of the partition. The graphs do not change the picture: the data-transfer speed of both HDDs fluctuates depending on how lucky the particular head/surface pair is, but the Seagate is overall faster. It seems to have a somewhat higher recording density with some reserve for further growth. As a result, the Scorpio Black is somewhat slower than its Blue counterpart (which has a lower spindle speed but higher recording density) whereas the Seagate is faster than both products from Western Digital. On the other hand, it is unable to catch up with the last-generation 3.5-inchers (by the way, the 3.5-inch Seagate is ahead of the 3.5-inch Western Digital, too).

And what about cache memory speed?

• Buffer speed of Western Digital Scorpio Blue, 500GB
• Buffer speed of Hitachi Travelstar 7K200, 200GB
• Buffer speed of Seagate Momentus 7200.2, 200GB
• Buffer speed of Seagate Momentus 7200.3, 320GB
• Buffer speed of Western Digital Scorpio Black, 320GB
• Buffer speed of Seagate Barracuda 7200.11, 320GB
• Buffer speed of Western Digital Caviar Blue, 320GB

Judging by the diagram, it is all very simple: the previous-generation 2.5-inch drives are limited by the interface bandwidth whereas the new generation works on full-featured SATA-300 and is no inferior to the 3.5-inch products. Seagate’s HDDs would win this test if it were not for the graphs. If you take a look at them, you can see that the read and write speeds of Seagate’s drives (of both the desktop 7200.11 and compact 7200.2 series) grows up quickly until 256-sector blocks (128KB). Then, there is a sudden slump, especially at writing, followed by a smooth rise. There are performance peaks at data block sizes that are multiples of 256 sectors, but the speed is not high: the read speed remains below 200MBps and the write speed is just barely above 100MBps. Western Digital’s HDDs also have a performance peak at 256-sector blocks, but the performance hit after that peak is not so dramatic. Thus, we think that Western Digital’s products are overall better in this test.