Today we have a look at the latest and hopefully greatest ATA hard disk drives from IBM and Western Digital and compare them with the Maxtor D740X. In our recent ATA 133 review the D740X came out very strong, besting our ATA 100 reference disk in all categories. In autumn 2001, when Maxtor launched the D740X series, it was safe to say that it was together with IBM's 60GXP the fastest ATA disk around. The question is: Can the D740X hold on or do the newcomers dethrone it?

Maxtor, IBM and WD - click to enlarge

The Hard Disk Drives in this Test:

We would have preferred to compare disks with the same capacity. That however was not possible as the tested Western Digital "JB" series is not available in the mainstream 40 GB storage capacity which we use as reference to compare our results. On the other hand, the Maxtor D740X is not available in a 100 GB version.

Maxtor DiamondMax Plus D740X
The D740X's prominent feature is its ATA 133 capability. In theory ATA 133 is providing 33% better bandwidth than ATA 100. The general understanding however is that ATA 133 gives headroom which is not useable. High-end ATA 100 hard disk drives transfer around 40~45 MB/sec. They are running at "only" 40% to 45% of their theoretical maximum transfer speed, because cables, connectors, and magnetic interference as well as the OS layer, firmware, and drivers are limiting factors. The good D740X performance seen in our previous review is probably the result of improvements in some of the many others areas that determine hard disk performance such as the mechanics, the control circuitry including the disk microprocessor, and the firmware. But it is most probably not related to ATA 133. Whatever the reason is, the D740X performed clearly better than our reference ATA 100 disk. The D740X is available with a "fluid" or "ball" bearing motor and comes in 20, 40, 60, and 80 GB. We used the 20 GB version for our test. The Maxtor D740X product data sheet with more details can be found here.

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Western Digital Caviar 1000JB
The "JB" hard disk drives come with an 8 MB disk cache/buffer and has therefore a unique position in the ATA disk market: Regular ATA disks, such as the other contenders in this test, have only a 2 MB cache. In theory the larger cache (or buffer) improves performance because there is a reduction in the number of physical accesses to the disk. This allows data to stream from the disk uninterrupted by mechanical operations. Obviously Western Digital intended initially to offer an 8 MB cache only for their high-end disk with 100 GB for a limited period of time and called it therefore "Special Edition". Due to high market demand for the initially launched 100GB capacity version a complete "Special Edition" line-up has been established and comprises now 80 GB, 100 GB and 120 GB versions. We tested the 100 GB model with the product number "1000JB". The product data sheet can be found here:

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IBM Deskstar 120GXP
The 120GXP is the latest descendent of a very successful line of hard disks, which consistently made it to the top in competitive tests. Unfortunately the GXP line included also a "bad child", the 1999 released 75GXP. Although performing very well and initially the top choice for high-end users, the 75GXP was later troubled by an obviously unusual high failure rate. Our 75GXP "autopsy" is here. It looks like that IBM could later solve the obviously heat related problem with the even faster successor to the 75GXP, the 60GXP. Unfortunately there are some reports of similar failures in that series also. At first glance IBM's 120GXP looks quite unspectacular as it offers neither ATA 133 nor a bigger than usual disk cache/buffer. Like the Maxtor D740X the IBM 120GXP 40 GB version comes with only 1 platter. Fewer platters are mechanically desirable because it reduces noise and vibrations; the mass the spindle has to move is smaller, and problems aligning the heads are less likely. The 120GXP, available since the beginning of 2002, comes in 20, 40, 60, 80,100 and 120 GB versions. We tested the 40 GB version. A very detailed 120GXP product data sheet can be found here (warning: 197 pages!)

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