Seagate was the first hard drive manufacturer to launch a native SATA hard drive with the Barracuda 7200.7 but truth be told it wasn’t particularly fast or impressive. The 7200.8 update was the drive that the 7200.7 should have been, and now we have the 7200.9 which meets the SATA2.5 specification. The headline change is the move from a 150MB/sec interface to 300MB/sec but we all know that this will bring minimal benefit when you are running a single hard drive as 150MB/sec offers plenty of headroom. Instead we should concentrate on the less obvious changes such as the addition of Native Command Queuing which is intended to transfer data more quickly between the hard drive and processor.
Other changes between the 7200.8 and 7200.9 are small but welcome with the idle acoustic level dropping from 2.8bels to 2.5-2.8bels depending on the model, idle power consumption drops from 7.2W to 6.9W, the seek power consumption drops from 12.4W to 8.1W, and the new drives use ClickConnect which should prevent your SATA cable from coming loose.
Internally the 7200.9 continues to use a spin speed of 7,200rpm and hence a rotational latency of 4.16ms with an average seek time of 11ms. The new drives use a maximum of four platters to give capacities that start at 80GB and which go up to an enormous 500GB. The 80GB and 160GB drives have a single platter and 8MB of cache, The 200GB and 250GB have two platters and 8MB cache, the 300GB has two platters and 16MB cache, the 400GB has three platters and 16MB while the 500GB has the full four platters and 16MB cache.
A small amount of work with a calculator shows that the 7200.9 uses a range of areal densities between 100GB per platter and 160GB per platter. The 500GB model comes in at the lower end of the scale with 125GB per platter while the 80GB (single platter, single head) and 160GB (single platter, dual head) has a density of 160GB per platter. Areal density is a good indicator of performance so while we weren’t surprised that Seagate sent us the 500GB model to review, what we’d have really liked was the 160GB version.