Windows 7 and IOPS is the most challenging, least understood and most frequently encountered resource bottleneck that stalls todays desktop virtualization projects. Many of these projects are Windows 7 migrations which are one of the key IT initiatives which are driving VDI adoption today. However, many IT organizations planning a Windows 7 migration with VDI are unaware that the combination of Windows 7 and Anti-virus more than doubles the amount of memory and IOPS required per desktop compared to Windows XP, which will significantly decrease virtual desktop density per server and will degrade virtual desktop performance. As a result, the storage architecture is often undersized for Windows 7. This leads to desktop performance and budgeting issues when more storage is required to fix the IOPS bottleneck.
Jim Moyle has written a very in-depth white paper on the subject of Windows 7 IOPS and how to tune for VDI. This white paper covers things like Windows 7 Queuing, SuperFetch, ReadyBoost, Ready Drive, and more. I highly recommend reading this.