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Performance in Intel IOMeter

Sequential Read & Write Patterns

From the low-level IOMark to the synthetic IOMeter. IOMeter is sending a stream of read and write requests with a request queue depth of 4. The size of the requested data block is changed each minute, so that we could see the dependence of the drive’s sequential read/write speed on the size of the data block. This test is indicative of the maximum speed the drive can achieve.

The numeric data can be viewed in tables. We’ll discuss graphs and diagrams. It is no good drawing 14 graphs in a single diagram (it is hard to make out anything in the resulting mess), so we will divide the graphs into two diagrams: one for 5400rpm drives and 4- and 5-platter models, and the other for the fastest HDDs (i.e. with 3 platters and a spindle rotation speed of 7200rpm). Thus, we have two groups of drives: slow and fast ones.

Yes, every 3-platter 7200rpm model has a top speed higher than 100MBps indeed. And the Seagate even notches 123MBps. However, the HDDs reach this speed on different data blocks. Being the best with small data blocks, the Hitachi 7K1000.B accelerates to 100MBps on 4KB data blocks. The Hitachi E7K1000 and WD RE3 reach that speed on 8KB data blocks. The Seagate and Caviar Black need at least 32KB data chunks for that. And Samsung’s models both reach the speed of 100MBps on 64KB data blocks.

The HDDs differ with small data chunks, too. Hitachi’s drives are good then, the 7K1000.B being ahead of the E7K1000. The WD RE3 is fast, too. The Seagate and WD Caviar Black start out at a good speed but slow down afterwards. Samsung’s drives are a disappointment as they are far slower than the others at processing small data chunks.

Seagate’s 4-platter drives notch 100MBps, too. Western Digital’s 3-platter 5400rpm models are only 5MBps behind them. Hitachi’s 5-platter model and the 4-platter Green drives from WD are slow at 80MBps.

The video applications oriented SV35.3 model is different from Seagate’s ordinary drives: it achieves its top speed on 4KB data blocks like the best of its opponents. The WD Green with 3 platters and 32MB buffer is the only “slow” drive that can do the same.

The drives are all worse at sequential writing than at sequential reading but most of the characteristic features are the same. The “fast” Seagate has the best top speed while the two drives from Samsung are worse than any other 3-platter 7200rpm model in terms of top speed and in speed of processing small data chunks. The most notable change over the read speed results is that the WD RE3 is now unrivalled when processing small data chunks while the Hitachi drives are not faster than their opponents. The Hitachi E7K1000 is slower than the 7K1000.B again while the WD Caviar Black falls behind the WD RE3 on large data blocks.

The second group of drives has the same features at both reading and writing, too. The Seagate SV35.3 differs for the better from the desktop model while the 3-platter WD Caviar Green with 32MB buffer is excellent on small data blocks.

Thus, WD’s drives with 32 megabytes of cache memory deliver excellent speed when writing small data blocks. The Caviar Black is somewhat slower than them. These drives are good at reading, too, but Hitachi’s new models are competitive to them at reading. The new drive from Seagate (with 3 platters) is unrivalled in terms of top sequential speeds.

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