Recently, however, there has been a growing realization that input/output operations per second (Disk IOPS) is a better measure of responsiveness than RPMs for several reasons:
- First, Disk IOPS are better at measuring multi-tasking capability and responsiveness of a hard drive than RPMs.
- Second, the cost of hard drives is based on IOPS not on RPM.
- Third, the growing popularity of flash-based Solid State Drives (SSD) is another reason for rethinking RPMs.
For more description regarding each step you can read here.
A hard disk drive with higher IOPS numbers is more responsive and able to multi-task better. For example, you can download large files, play a favorite music, run anti-virus scan and surf the internet with opened 30 web browser windows at the same time without any lag.