Both the bundled Windows XP driver and the latest driver from the Promise website as of this writing (mid-January 2004) have problems when the array is used as the boot drive. The performance of the array with these drivers was severely impaired under both RAID 0+1 and RAID-5. Specifically, while the reading/writing would sometimes burst at a normal speed, it would run into lag where the disk activity would pulse and progress would be unacceptably slowly.

In a forum on 2cpu.com, others confirmed this issue and pointed out that a beta driver was available from Promise that solved this problem. The beta driver is listed on the Promise website, but under the category of the SX4000 model controller. A newer driver,, is also available by emailing Promise technical support. Using the version beta driver for the SX4000 resolved the boot drive issue, and this was the driver used for the benchmarks. This driver requires the BIOS be flashed to version