7,200 RPM WD4000KD Caviar
The WD4000KD comes with 16 MB of cache and a Serial ATA/150 interface. The major differences compared to the 10,000 RPM WD Raptor are the drive's performance and capacity. The Raptor suffers heavy defeat in the cost per gigabyte category, as it is at least six times more expensive per gigabyte than the 400 GB WD4000KD. The benchmarks will show what the performance differences are like.
10,000 RPM WD1500ADFD Raptor
The Raptor is the undisputed champion in the desktop hard drive arena, but it also is the most expensive drive. The WD1500 Raptor only uses a Serial ATA/150 interface, which is still enough. If you have a look at our Interactive Hard Drive Charts you will notice that no other drive outperforms the Raptor, although more and more products run a 300 MB/s SATA interface. Clearly, SATA interface speed should not have an influence on your purchasing decision.