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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.

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

The Seagate 7200.11 is the leader of this test thanks to its 7200rpm. The second-best Seagate LP is very good, too. Its data-transfer rate of 120MBps is very high, especially for a HDD with lower spindle rotation speed. Does it benefit from having an extra 500rpm in comparison with the other power-efficient HDDs? Yes, but not much. If you take a closer look at the data-transfer graphs, you will see that the speed of each HDD varies wildly depending on how lucky the specific surface/head pair was during formatting. And this fluctuation can easily negate any advantage from the somewhat higher spindle speed.

For all those fluctuations of speed, one graph is especially interesting as it differs greatly from the others. It is the graph of the 1.5TB model from Western Digital. With full-size platters, the speed at the beginning of a disk is roughly twice as high as at the end. Here, we see that the speed at the end is obviously too high. This seems to be the consequence of the HDD’s using only the fastest zones of platters which are not formatted for their full capacity.

Now, let’s check out the speed of the HDDs’ cache memory.

Western Digital’s HDDs all behave in a similar manner when working with the cache buffer. They are all somewhat slower than their opponents in terms of top speed. But the main differences are in the graphs. That is, in the speed of processing large data chunks. The Samsung looks best here. It has no slumps and its write speed is not much slower than its read speed: the graph is very neat.

Western Digital’s products are somewhat worse in this respect. Their writing is slower than their reading and subject to fluctuations. The RE4-GP stands out among this company’s products. Its speed slumps on very large data blocks. The new firmware seems to be not quite optimized for the enlarged cache.

Seagate’s HDDs are far from good, too. The 7200.11 suffers a performance hit on data chunks larger than 256 sectors (128KB): the read speed plummets to 150MBps and the write speed, to 100MBps. As a result, the very purpose of the cache buffer is negated because the speed is comparable to the speed of sheer writing to platters. The new LP is better in this respect. Its speed does not fluctuate too much. Its read speed does not sink below 200MBps and its write speed is a decent 150MBps. Still, the example of the Samsung drive proves that firmware can be improved even more.

 
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