The main use of Western Digital's Raptors is in servers, although they are marketed at high-end enthusiasts and not so much at enterprise. As far as I know, they're pretty much the fastest consumer hard drives available, just in every way. As well as being able to read and write data faster, they are designed to be able to handle utterly random requests. The faster RPM means the magnetic read and write heads can also change position very quickly, but even for regular drives, that's a time measured in milliseconds, anyway. On a busy file server however, the milliseconds add up.
The cons? Cost per gigabyte is through the roof, literally 10 times more expensive for a 300GB WD Velociraptor versus a 1000GB WD Caviar. You don't get 10 times the speed in return. They also need a lot of power to do their magic, which in turn means a lot of heat. Different from the old Raptor model, the Velociraptor is actually a notebook-size drive with a massive metal heatsink to bring it up to desktop size. Probably more noticeable, is that they are typically among the noisiest of hard drives.
You've included a pair of GTX285s, so I'd assume extreme speed floats your boat more than value. However, space is still a quality to consider. At a rough estimate, I'd say a drive like a Velociraptor is around 30% quicker than the average hard drive, but many such drives include 50-70% more space, as well as being cheaper.
Of course, the other alternative is to add more hard drives later.
mann thats 1.35 lacs I can only dream of that much affordability.
