IRQL_NOT_LESS_OR_EQUAL with BIOS 79 or Later for Intel® Server Boards and Systems


Error Messages



Windows* may blue-screen with the error message IRQL_NOT_LESS_OR_EQUAL when the installation media does not include an integrated service pack.

Starting with BIOS 79, support for enhanced sleep states was added, which relies on code found in the service packs as listed below.

  • Windows Server* 2003 32-bit and 64-bit requires Service Pack 1
  • Microsoft* Small Business Server 2003 requires Service Pack 1
  • Windows* XP 32-bit requires Service Pack 2


  1. Temporarily disable BIOS setting
    1. BIOS > Advanced > Processor > Configuration, and Disable 'Core Multi-Processing'
    2. Install core OS, then install service packs
    3. Re-enable 'Core Multi-Processing'
  2. Install with media that includes the integrated service pack (slipstreamed)


Note Microsoft* Windows 2003 Release 2 is not affected with this issue.