An evolution, but not a revolution - that is how we'd like to describe Hitachi's new 4 TB hard drives. The performance is excellent. With its high data density the 7K4000 is the fastest 7,200 RPM drive that we've ever tested, while the 5,400 RPM 5K4000 almost achieves 7,200 RPM-like performance. The good performance and huge storage capacity luckily do not come at a high price. They don't cost more than typical 2+ TB drives if you look at the price per GB.
The noise production is acceptable, even though it could have been lower. The idle power usage could have been lower as well, especially considering the high probability that disks like these will end up in a Home Server or NAS.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips