We feel that our test and benchmark results confirm what we stated after finishing our recent hard drive roundup: the market is ready for some improvement in the areas of hard drive capacity and performance. Don't take that as an indictment of this particular drive; the new 400 GB offering from WD is a good performer, with quiet operation and amazing capacity. But it was realized only by using current technology and adding more platters to the hard drive family - the same way Hitachi (and IBM before them) has been doing for years now. At the end of the day, the 400 GB drive is not noticably faster than the 320 GB WD3200JB/JD.
The WD4000 compares favorably to other WD drives, but remains behind its current competitor from Seagate (7200.8) when it comes to low level performance (except for the access time test.) This makes it rather clear that the next generation hard drives should either be divided into high-capacity and high-performance models (preferably running at higher rotation speeds) or get a serious push from new technologies such as perpendicular recording.