Turning off Hyperthreading

[Lanceor]

Has anyone tried turning off Hyperthreading?

 

The theory is that hyperthreading allows a quad-core processor to run up to eight concurrent threads at 50% speed. While great for general computing, Skyrim (and games in general) requires maximum on-demand performance from fewer cores. Having to share a core with another thread will actually worsen its performance.

 

Also, to quote the CPU affinity - two different approaches thread:

EDIT: From the Intel support forum:

 

"On a hyper-threaded processor with N physical cores and 2N hardware threads, it is often better to limit the number of 'busy' threads to N for extremely compute intensive applications (like Skyrim). This is because hyper-threading shares the resources of a single core between two hardware threads and if both of these threads are trying to run highly compute-intensive operations they compete (sometimes inefficiently) for the resources of that single core - often ending up running more slowly than a single thread running unimpeded on that single core. So what happens to the other hardware thread if you do this? Not much - it mostly just 'sleeps', servicing the occasional interrupt in the background but consuming almost no resources (and by servicing those background interrupts, it keeps the busy thread from having to switch context to service them). So you're best off to leave things alone and let Skyrim utilize the processors the way it is designed to do..."

 

So, it might make sense to try and prevent Skyrim from utilising hyper-threading if it were running many threads, but Skyrim doesn't appear to do that, and this is not likely to be an issue. I doubt there is anything to be gained by forcing Skyrim to ignore available physical cores. I suspect that this is one of those tweaks born from Chinese whispers of a fuzzy understanding that Skyrim only runs a couple of threads, and doesn't benefit much from several cores.

By turning off hyperthreading, Windows is still managing how the CPU is utilised. However, it ensures that high-usage processes get cores all to themselves.

 

I do have some anecdotal results from my non-scientific "tests". However, I'll spoiler them so that anyone planning to test it can do so with an open mind. :)

 

 

Turning off Hyperthreading did seem to improve performance for me. Most noticeably, mouse-stutter when panning around seemed greatly reduced. I can't be 100% sure that it's not a placebo effect though.

 

[Aiyen]

I guess it is rig dependent... Since the motherboard does play a very large role when it comes to how effective the CPU communicates with the RAM etc.

 

I have tried out all the threaded options for skyrim without any noticeable gains or losses in performance.

As for disabling hyperthreading entirely.. then that is just not an option for me. I like my hyperthreading for other things, and if I did not want it I would have saved the money and just bought a core i5 instead of a core i7.

 

Also most benchmarks I have seen have shown no noticeable drop in performance on the core i7 models compared to the core i5´s In fact most of the time they perform a little bit better as I recall. But again that is game dependent... as for programs that are not games, then the difference is more obvious in favor of the core i7´s.