Hi roberto,
If you don't see any difference with hyperthreading on or off, try an experiment and turn it off for at least a month, then report back.
I know it is nice to be able to say that you have 8 processors running - the youngsters I build computers for all want bragging rights with as many processors as possible which partly works on windows but not on OS/2 that runs much better on real cores, not partial cores that need a real core to work - and there is the problem, if the real core is serving a partial core and misses the timing for something it should be doing we get traps and exceptions.
Your decision, live with traps and exceptions and fake processors or use real processors only.