Ultra ATA/66 versus Ultra ATA/33 Comparison

The Ultra ATA/66 interface has been with us for a little over a year now, and most of the hard drives currently available support this standard. With the promise of double the transfer rate over the Ultra ATA/33 interface, Ultra ATA/66 drives seem to be the Holy Grail to our hard drive performance problems. But just how much benefit does the Ultra ATA/66 standard have on the drives that are currently available on the market?

While this comparison is not an attempt to downplay the importance, or need, for the Ultra ATA/66 interface, as current hard drives are becoming increasingly faster demanding more data transfer bandwidth, it does help to show that the choice between these two interfaces has very little to do with performance when using current generation drives.

There is no doubt that the aging Ultra ATA/33 standard will quickly become inadequate to keep up with the ever-increasing performance of hard drives. Industry analysts estimate that hard drive performance will continue to grow at a rate of 40% each year, and with current hard drive performance quickly approaching the Ultra ATA/33 barrier, the Ultra ATA/66 standard is truly needed, as is the future Ultra ATA/100 standard.

Your need look no further than our own review on the Maxtor DiamondMax Plus 40 (Ultra ATA/66) hard drive to see how the current hard drive technology is right at the edge of the Ultra ATA/33 capabilities and will soon need the extra breathing room offered by Ultra ATA/66. Turning in sustained data transfer readings greater than 30 MB/s on the outer tracts, the Maxtor DiamondMax Plus 40 series of drives, would utilize all of the Ultra ATA/33 specs bandwidth.

While we are not trying to downplay the need for the Ultra ATA/66 standard, we do think it needs to be looked at for what it is: a standard, not a performance booster. While the implementation of the Ultra ATA/66 standard does offer slight performance gains in current drives; these gains are mainly due to the burst transfer rate of data, and not the sustained transfer rates. If the requested data happens to be in the cache memory of a hard drive, this data can be transferred in bursts at up to 66 MB/s. This “burst” transfer of data provides a boost for business type applications, where the odds that your next requested block of data has already been pre-loaded into the drives cache are greater.

If your application requires more data than can be fit into your hard drives cache, or if the data requested is not preloaded into the cache memory, then you drives data transfer rate will drop down to the actual physical media transfer rate. Currently, this is below the even the 33 MB/sec of the Ultra ATA/33 standard, although some of the newer drives are fast approaching this threshold. In everyday use of your computer, you will most likely encounter a combination of the above two scenarios, so although you will notice a slight performance gain, it won’t be quite as dramatic as the advertising on the box makes it out to be.

So to summarize, the purpose of this article is not to discredit the need or benefits of using the Ultra ATA/66 standard, but rather to objectively compare the Ultra ATA/66 standard against the older Ultra ATA/33 standard, to see just how much performance the current generation of drives are able to gain by utilizing the newer standard.