Extra heat with Hyperthreading off?

[mmenarry]

Folks, a quickie for y'all-
Running a 2.8 GHz P4, 800 MHz FSB, with Hyperthreading.
Gigabyte 8IK1100 mobo.
Updated the bios recently, which required the HT to be switched off while the update was in progress.
Just happened to notice that the CPU temp increased significantly while the HT was off.
Normal CPU temp with HT on is 33/34 degrees C.
With Hyperthreading off, the temp is 43/44 degrees C.
Back down to normal temp with the HT back on again.

Is this normal, or is paranoia creeping up on me?

TIA
Michael

 

[wantstolearncfm]

Could be a huge system load with the bios upgrade, but i guess to sustain the same speed with HT off the processor has to work a darn site harder?

 

[PraetorianWS]

As far as I can tell this is normal. My CPU increases about 5 degrees with HT off.

 

[cadaveca]

the reason that your cpu temp is higher is because without hyperthreading, you are using more processing power for the same tasks. Hyper threading is a "virtual" processor, like and extra set of registers for handling data. because of this, with hyperthreading enabled, tasks that normally use 100% of your cpu, use only 50%, and hence your lower temps.


the only right answer to "why?" is: "why not?"

 

[mmenarry]

Cheers, folks!