As faster and faster disks evolve, chances of the disk being the issue become less likely. Redundant Array of Inexpensive Disk (RAID) and striping technologies are not really IIS-related performance tricks, but they can help increase your server’s overall performance. The real effect on hard disks depends on how much RAM your machine has.
What Causes Hard Disk Pressure?
Typically, pressure is a matter of the amount of disk reads and writes. A Web server that has a high ratio of reads to writes tends to perform better. The Reliability and Performance Monitor is a great tool for analyzing the total number of reads and writes a Web server generates. If your application requires a lot of writes, you should have faster disks and a RAID implementation ...