Spoilt For Choice: UltraATA/100, SATA Or SATA-II?
SATA (left), UltraATA (right).
Although it's true that, technically, Serial ATA has the higher bandwidth compared to UltraATA with 150 MB/s (SATA-I) and 300 MB/s (SATA-II) against the latter's 100 and 133 MB/s, this value merely describes the maximum theoretical bandwidth of the interface between drive and computer system. In practice this is only interesting when data is read from the drive cache or written to it. Otherwise, the magnetic storage medium remains the bottleneck in the system. This verdict could be applied to the whole computer as well if you disregard for the moment optical drives or various interfaces such as USB, FireWire and Ethernet.
Modern 3.5" hard drives in the desktop domain score maximum transfer rates of 60-70 MB/s; because of their low speeds and smaller platter diameters, notebook drives in 2.5" manage 30-40 MB/s. In practice, these values are even far less after the file system has taken its toll.
The question of whether to go for SATA-I or SATA-II with 300 MB/s is thus almost always irrelevant in this context. Both standards offer the plus of simple cabling to an equal degree. Much more important is the availability of native command queuing. With the aid of this function, many SATA and all SATA-II hard drives can examine incoming commands, re-sequence them if necessary and execute them in the most efficient order. In case of doubt, the best thing to do is to check the manufacturer's spec sheets, which are bound to clear up any uncertainties.
The only question remaining is whether you want a model with UltraATA interface now or not. Our verdict is that, if possible, go for SATA. The price differences between UltraATA drives and their SATA cousins are very little. You should shell out the extra cash today because, at the latest by summer next year, more and more computers will be delivered entirely without UltraATA ports. You'll kick yourself if you have to buy a controller later.
