Re: If i disable hyperthreading...
I don't think so, hyperthreading is supposed to improve your processor's performance under certain workloads.
And judging by your two computer's temperatures from your other post I think Mammikoura is right, you may have damaged your processor.
Intel Core 2 Duo E8400 @ 3.7GHz
4GB OCZ PC-6400 RAM
Samsung Spinpoint 1TB HDD
ATI Radeon HD4890 with VoltageTweak
OCZ Stealth XStream 600w PSU