I install Linux Mint 11 on the computers I currently build and I use the system profiler to check system components and run the CPU Blowfish benchmark test. These cpu's perform like a dual core system. Here are some of my results:
- Intel Duo Core E2140 runs the Blowfish test at 10.75 seconds.
- Intel Pentium 4, HT 3.2GHz run the Blowfish test at 11.45 seconds.
- Intel Pentium 4, HT 3.0GHz run the Blowfish test at 11.66 seconds.
As you can see the P4 HT's perform almost as fast as the early Duo Core processors. So my recommendation is not to get rid of your HT's yet, they should provide lots of years of good service still.