Background

Hard disks always have been and will remain the slowest parts in computers due to their mechanical nature. Compared with a pure electronic part, like memory, an electromagnetic part like the hard disk is very, very slow; RAM speeds are measured in nanoseconds, hard disk speeds in milliseconds. On the plus side, hard disks have increased in size and several hundreds of GB are possible in the average home PC. Some may also argue that technical improvements have increased the MTBF (Mean Time Between Failure) i.e. provided increased reliability, and that advances in technologies like Fluid Dynamic Bearing have reduced the noise drives generate. 

There is one thing, however, that hard disks just haven't done very well on - speed. Today's buzz words like UDMA, SATA etc. haven't made a 266 MHz-to-3.6 GHz type of leap in performance. True, disks are faster now than ever before but, relative to advances in CPU architecture, hard disks are advancing at a very leisurely rate. In terms of metrics all they've done is move from 5400 rpm to 7200 rpm on the spindle speeds and from 2 MB to 8 MB of onboard cache - and that's it. 

The storage space has increased tremendously over time and the cost has deceased to less than $1.00 per GB, a figure that would have been simply unbelievable as little as two years ago. (There are downsides to larger sizes, of course, in that the more the data you have on your platter the longer it takes to find any one part of that data).

All of the main hard disk manufacturers today, such as Maxtor, Western Digital, Seagate, and Hitachi/IBM, offer near identical 7200rpm 8mb cache PATA UDMA133 /SATA UDMA 150 hard disks. The products vary only slightly in factors such as heat output, noise generated, and warranty. 

There is one exception, the Western Digital Raptor, an enthusiasts' drive that has received rave reviews. The Raptor is optimistically referred to as an "enterprise class" drive because it spins at 10k rpm.  This offers faster read and write speeds and faster access times than any 7200rpm drive. The Raptors are available in only two sizes - 36.7GB and 74GB, and are often compared to SCSI drives in performance. Enthusiasts even combine them in RAID 0 configurations to push their performance past many older SCSI drives.

Maxtor's new drive, the DiamondMax 10 (sic) goes down a different route. Maxtor decided to forsake faster spindle speeds to offer a doubling of the onboard cache and, importantly, support for Native Command Queuing. 

The increase in cache helps with the storage of I/O requests from the controller and speeds up the user experience. Accessing the cache, which runs at RAM speeds, is faster than accessing the disk platters so the more the data that can be stored in cache the more the benefit to be seen in many applications. Native Command Queuing is a SATA command protocol offering increased hard disk speeds. It involves a more intelligent routing of the hard disk heads when they have several bits of data to read. It minimizes the number of times the platter has to spin for the heads to access all the data requested and this reduces the latency. Officially, it is a powerful interface/ disc technology designed to increase performance and endurance by allowing the drive to internally optimise the execution order of workloads.

How does the 16 MB of cache and the NCQ feature of the new 7200 rpm DiamondMax 10 compare with today's top 10K rpm Raptor with 8 MB of cache? We decided to take them for a, er, spin.

DiamondMax 10 specifications