GA-8IEXP hyperthreading

I have a 2002-vintage GA-8IEXP version 1.2 motherboard at home. It had
a 2.4GHz Pentium 4 Northwood CPU. I flashed the BIOS to Gigabyte
version F9 (Award 6.00 PG 11/01/2002) which supposedly allows
hyperthreading, and then installed a used 3.06GHz Pentium 4 Northwood
(SL6PG) CPU which supposedly has hyperthreading capability. CPU-Z
reports the CPU is Family F, Model 2, Stepping 9, Rev D1 and the
chipset is i845E Rev E0.

I was hoping that hyperthreading would speed up simultaneously running
an FPGA compiler and an MS-DOS math program that I use for simulation
of the FPGA outputs. When I run both programs, a compilation takes up
to four times longer than when I run only the compiler, 24 minutes
versus 6 minutes. 6 minutes is slow but 24 minutes is intolerable. A
computer at work with dual-core CPU and dual-channel memory runs the
compiler in the same time (2.5 minutes) regardless of the MS-DOS
program. A faster computer at home is impractical right now.

The 3.06GHz CPU now runs stable and cool but without hyperthreading,
according to Belarc Advisor and Windows XP Task Manager. I have not
found anything in the BIOS setup about controlling hyperthreading.

How can I enable hyperthreading?