Turning off hyperthreading

[Paul K]

I've been asking this on various forums and can't get an answer, so I'll try here. This is the actual specific question:

Does disabling the virtual cores by using Task Manager/Processes/( process name )/Set Affinity have exactly the same effect as disabling HT in BIOS ?

This time, I'm not going to go into why I want to turn HT off, or the pros and cons of doing so, because that then becomes the discussion, rather than the specific question above. So, just that one query - BIOS setting, Task Manager or doesn't it matter ?

Thanks to anyone who can give me the definitive answer.

[Vancouver]

Bios every time. Stabler than messing with the Task Manager in my experience which caused lock ups and such. FSX for me prefers the Bios setting too but other more modern programs prefer hyperthreading on.

[TSR2]

HT and affinity mask ARE different. Turning off HT in the BIOS actually stops the core from running the second thread at a hardware level. The effects vary slightly depending on processor generation and motherboard though. Hope its useful.

[Paul K]

Very useful, Ben. That's what I was after - the differences, if any, between turning HT off and using affinity mask / Task Manager. Alex, thank you also. The only other programs I have that might suffer are DCS, Arma 3 and Project Cars.

There is speculation on the LM forum that with some systems, turning HT off reduces VAS use, and in some instances, enhances frame rates. I'm not concerned with frame rates now, as I recently upgraded my GPU, but as I'm becoming more interested in long distance airline flying, VAS is a consideration.

Time to experiment then. Thanks again, both.