Losing performance through Hyperthreading on NT 4.0 ?

[Holger]

Windows NT 4.0 does not support Hyperthreading. It is restricted to
physical processors.

Despite from that it is possible to enable Hyperthreading in the
computers bios. This means all the MP-tables in the bios are created
AND the processors are configured for active Hyperthreading mode when
the systems is starting up.

In this configuration NT 4.0 is only using CPU0 of the HT-enabled
processor.

Is it possible that this has some sort of negative effect on the
maximum performance of the processor?

Should we recommend as a general advisory that Hyperthreading should be
deactivated on Systems running Windows NT 4.0?

Best regards,
Holger

[Calvin]

Hi,

Interesting remarks. Having not had suitable hardware to play with here I can
only repeat previous reports made in these newsgroups.

I recall reading at one stage that somebody had enabled HyperThreading, and the
NT install had detected the system as a multiprocessor platform, and installed
the HALMPS.dll as a result.

The system worked and reported as having two processors, but I do recall them
also reporting that there were some stability issues, and they ultimately
abandoned the configuration and returned to a single processor HAL and NT4 setup.

Calvin.