Rotational frequency has become a big selling point lately, so you shouldn't have too much problem finding out what the rotational frequency of your HDD is when you go to buy it. Now of course the faster it spins, the faster it can read from the disk, but be aware that the faster it spins, the more wear is put on the drive, and the more likely it is to encounter errors and malfunctions later in life.

If you know anything about physics or engineering, then you know that moving parts produce friction and wear, and a faster spinning platter means more friction, and so more wear on your drive. Of course the faster it spins the faster it can read data from the platter. Well again you backup your data as much as possible and you get the fastest spinning drive money can buy and 15000RPM for SCSI and some Serial ATA devices. Thus look for a "7200RPM" label on the drive you're idea of getting.

Notice 4 major feature related with speed That was done purposely to give you a sense of the importance of speed in the hard drive, because they are very slow creature, and for your gaming knowledge you don't need an enormous hard drive so much as a fast . To raise speed considerably more you can set up a RAID, which is a network of hard drives which share part of the same data, such that accessing data takes 1/n time compare to 1 hard drive. To do this you actually need a hardware RAID chipset, which are normally included on higher end main boards.