Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: Shawn Astrom on 2017-04-28, 06:01:27

Title: Hyper-Threading OFF or ON?
Post by: Shawn Astrom on 2017-04-28, 06:01:27

Hey everyone. I have a 40 core 80 thread computer and I am noticing that with HT turned off I am getting much improved render performance in 1.6.

But, if I have HT turned on I am getting better performance with the 1.3 benchmark...

Does anyone have any ideas about Intel HT technology and weather or not it should be turned on or off? I have a feeling this might not be true for lower core computers...

Thanks guys!

- Shawn

Title: Re: Hyper-Threading OFF or ON?
Post by: Charlie Nicols on 2017-04-28, 12:17:58

Typically for any render engine HT should be turned on. - More cores Physical or Virtual = Faster render speeds.

Not sure why turning this off would speed up renders in 1.6? I don't see the same result.

Title: Re: Hyper-Threading OFF or ON?
Post by: Juraj on 2017-04-28, 17:32:53

Can you post these results in screenshots ?

Title: Re: Hyper-Threading OFF or ON?
Post by: Shawn Astrom on 2017-04-28, 18:43:15

I will post first chance I get. In my initial test I built a simple cornel box and had it render to a 100 passes. With HT turned off using 1.6 it took 1:18 With HT turned on it took 1:57...

But with the 1.3 Benchmark with HT turned on it renders in :40 and with HT turned off I was getting :57...

I'll post some screenshots ASAP. I have a suspicion that there is some performance loss with many softwares once they see over 64 cores... Terragen 4 for example renders fast with HT off...

- Shawn

Title: Re: Hyper-Threading OFF or ON?
Post by: Juraj on 2017-04-28, 19:00:16

Quote from: astrofalcon on 2017-04-28, 18:43:15

I will post first chance I get. In my initial test I built a simple cornel box and had it render to a 100 passes. With HT turned off using 1.6 it took 1:18 With HT turned on it took 1:57...

But with the 1.3 Benchmark with HT turned on it renders in :40 and with HT turned off I was getting :57...

I'll post some screenshots ASAP. I have a suspicion that there is some performance loss with many softwares once they see over 64 cores... Terragen 4 for example renders fast with HT off...

- Shawn

There is a truth to this, because after 64 'threads', Windows will create groups (so 80 threads will becomes two groups), and softwares not optimized for groups, will only see a single one. HT off is band-aid for this, because in this exact case, 40 physical cores, is more than 40 virtual threads.

But Corona sees groups perfectly and I myself use few 80 thread nodes ( E5 2698v4).

With benchmarks it's good to remember not everything is perfectly multi-threaded, so the longer they are the better. With renders going for 1 hour+ I see almost perfectly linear scaling.

Title: Re: Hyper-Threading OFF or ON?
Post by: Shawn Astrom on 2017-04-28, 19:03:03

Good to know! I'll do another new test and them render a bit longer... I'll post my results here.

- Shawn