No HT without ACPI?

Hi,

I had to disable ACPI on my system because it caused a high load. While rebooting I noticed that the second CPU (P4 HT) wasn't found:

CPU: Trace cache: 12K uops, L1 D cache: 8K
CPU: L2 cache: 512K
CPU: Physical Processor ID: 0
Intel machine check reporting enabled on CPU#0.

CPU:     After generic, caps: bfebfbff 00000000 00000000 00000000
CPU:             Common caps: bfebfbff 00000000 00000000 00000000
CPU0: Intel(R) Pentium(R) 4 CPU 2.60GHz stepping 09
per-CPU timeslice cutoff: 1462.79 usecs.

enabled ExtINT on CPU#0
ESR value before enabling vector: 00000000
ESR value after enabling vector: 00000000
Error: only one processor found.
WARNING: No sibling found for CPU 0.
ENABLING IO-APIC IRQs

Is ACPI necessary for HT to work? This is with 2.4.21.

Cheers,

Jurgen