From the developer:
"The Intel Application Accelerator is a performance software package for Intel desktop and mobile PCs. It reduces the storage sub-system bottleneck, enabling faster delivery of data from the hard drive to the processor and other system level hardware. This software provides accelerated disk I/O for games, graphics applications, disk utilities, and media authoring applications. Intel Application Accelerator enables a performance-enhancing data pre-fetcher for Intel Pentium 4 processor-based systems and delivers faster overall system boot times by significantly accelerating the load time of the OS - enabling you to build Pentium 4 processor-based systems with a better overall end-user experience.
"Customers who are currently using the Intel Ultra ATA Storage Driver can upgrade to the Intel Application Accelerator for the latest enhancements and updates. Intel Application Accelerator has replaced the Intel Ultra ATA Storage Driver."