disabling multithreading

[glorybound]

Any reason to do this? I am reading some performance tweaks, and I read disabling multithreading is something to try.

[vlado]

Are you sure it's not "hyperthreading"?

Disabling multithreading will make you renders crawl as only one thread will be used to render.

Disabling hyperthreading has sometimes been suggested to speed up renders. I myself have never witnessed this effect - in my own tests hyperthreading always reduced render times between 10% to 30%, though I don't exclude the possibility that there are cases where it hurts the performance. I imagine this could happen if all threads try to access the same serialized resources, and more threads are competing for access. However most scenes are not like that.

Best regards,
Vlado

[instinct]

I think there were cases here were Hyperthreading in combination with unsupported RAM configurations caused clockspeeds to be lower or something like that.

I might remember that wrong though heh.

Cheers,
Thorsten

[glorybound]

Oops.. Typo. Yes. hyperthreading.

[Morbid Angel]

Oops.. Typo. Yes. hyperthreading.

I had my HT off for 5 years since I bought the xeon 5650, the HT caused more harm then it did good. Back then, max in particular had tough time with it, display issues, performance lags etc. But recently I turned it back on, and all is fine now (imagine how many max versions passed for 5 years) it adds 15%-20% performance boost during rendering, but in single threaded operations I question if its faster then with it off.

[glorybound]

good to know, thanks. I'll leave mine on.

[Rens]

Yeah single threaded tasks will be slower with HT on, so if you're using a lot of these (e.g. some sims or maxscript calculations) compared to rendering then turn off HT.

[Morbid Angel]

I also noticed something interesting. As I mentioned in the post above, I've had the HT off for years until recently I turned it on. After that, working with HT I've noticed a substantial performance drop while rendering and doing other tasks. For example, during rendering, browsing in chrome became impossible (though maya/max were set to lower priority). And doing other tasks while rendering just became really slow!

The rendering it self is faster but I think it taxes the system a lot more. I'm considering turning it off again as a workstation, it actually made things worse for me imo.

[Deflaminis]

I also noticed something interesting. As I mentioned in the post above, I've had the HT off for years until recently I turned it on. After that, working with HT I've noticed a substantial performance drop while rendering and doing other tasks. For example, during rendering, browsing in chrome became impossible (though maya/max were set to lower priority). And doing other tasks while rendering just became really slow!

The rendering it self is faster but I think it taxes the system a lot more. I'm considering turning it off again as a workstation, it actually made things worse for me imo.

It becomes more necessary to check "Low thread priority" with the HT. Everything seems fine then, in my experience.