Seagate Barracuda XT: ST32000641AS, 2TB
Seagate seems to be kind of superstitious. The new series of 7200rpm Barracudas was named XT rather than 7200.13. The new-generation drives have the same 500GB platters as the 7200.12 series but as many as four of them! The new feature is a 64MB cache. Western Digital was the first maker to install so much cache memory into its RE4-GP and Seagate follows the suit. Memory is not so expensive today, after all. We will see in our tests what benefits the enlarged cache brings about.
This is not the only innovation, though. Seagate has implemented a new type of the interface, SATA 600 (together with the introduction of SAS 6Gbps in the Seagate Cheetah 15K.7, by the way). As you may guess, the new version is backwards-compatible with the earlier SATA but doubles the data-transfer rate to 600MBps. Such a high bandwidth won’t be necessary for hard disk drive for the time being because the speed of sequential reading of modern 7200rpm models is only approaching the bandwidth of the very first SATA standard (150MBps). Thus, the second version of the SATA interface offers a double reserve of bandwidth.
The interface bandwidth is more important for SSDs and disk racks. For them, 600MBps is going to come in handy, but we are talking about HDDs here. The only performance gain we may observe is the speed of data access in the 64MB cache.
Western Digital Caviar Green: WD20EADS-00R6B0 2TB
We know this HDD, too: we have discussed it in our previous review. It was the first 2TB drive we managed to get and it is included into this review for the sake of comparison. By the way, this HDD has got a cousin with 32 rather than 64 megabytes of cache, called WD20EARS, but we don’t have it yet, unfortunately.