What is it?
SiS Hyperthreading patch - htpatch.exe

What does it do?
htpatch.exe - This is a patch for SiS users that use a CPU that supports Hyperthreading. It appears to be harmless, but some people without hyperthreading CPUs have reported a performance LOSS so you may want to do some benchmarking yourself on this.

Virus Precautions:
You'll want to keep an eye on this google search for any known viruses. The normal location of htpatch.exe is: C:WINDOWShtpatch.exe At this time my search shows nothing that you need to worry about.