Compaq Evo Workstations W6000 And W8000; Enabling/Disabling Hyper-Threading - Compaq Evo Workstation w6000 White Paper

Hyper-Threading Technology, New Feature of Intel Xeon Processor White Paper

Compaq Evo Workstations W6000 and W8000

The Compaq Evo Workstations W6000 and W8000 incorporate the new leading-edge Intel Xeon
MP processors and the Intel i860 chipset to achieve the next level of system performance. A
detailed discussion of the Xeon processor and the i860 chipset, including performance
advantages, can be found in the Compaq white paper [6] 1527-0501A-WWEN (April 2001)
Architectural Comparison of Compaq Evo Workstation W6000/W8000 with Compaq Workstation
AP550/SP750.
Compaq Evo Workstations systems arrive with Hyper-Threading technology disabled. This is
done for several reasons.
First, in order to see the real advantage of Hyper-Threading technology, most applications need to
be rewritten and recompiled for TLP and ILP. Recompiling with Streaming Single Instruction
Multiple Data [SIMD] Extensions (SSE2) can deliver additional performance gains. Not many of
the applications that are available today are recompiled to take advantage of HT. Therefore, the
majority of the existing applications will perform better with the two physical CPUs versus two
logical CPUs, which Hyper Thread Technology provides.
Secondly, the system with Microsoft Windows 2000 Professional Version and dual physical
processors cannot take advantage of Hyper-Threading technology since the Professional version
only supports up to two CPUs. Only the server version of Windows 2000 supports Hyper
Threading technology.
Finally, Windows NT does not support Hyper-Threading technology.
IMPORTANT: If a system was originally shipped with one CPU, the system may have an
Advanced Configuration and Power Interface (ACPI) Uniprocessor Hardware Abstraction Layer
(HAL). You will need to switch to 'ACPI Multiprocessor' HAL in order to use Hyper-Threading
technology.

Enabling/Disabling Hyper-Threading

This section outlines the steps to enable and disable the Hyper-Threading technology on Compaq
Evo Workstations W6000 and W8000.
Preliminary Steps
Before enabling or disabling the Hyper-Threading technology, perform these preliminary steps:
1. Check the firmware version at the boot up screen in the lower left corner to ensure that
version v01.12 is installed.
Note: If the firmware version is earlier than v01.12, then it is possible that the CPU in the system
does not have support for Hyper-Threading technology.
2. Flash the system with the firmware version v01.15 or the latest available on the Web.
IMPORTANT: If you are not familiar with the Compaq ROM-based setup, refer to Appendix A
for detailed procedures.
3. Check to see if the ACPI Multi-processor PC is installed on the system. See Appendix B for
details to check and switch to a different HAL.
167T-0202A-WWEN
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