Page 1 of 1
Handbrake cpu clock multiplier
Posted: Wed Mar 17, 2021 4:59 pm
by herald128bit
Help !!
Odd CPU clock multiplier behaviour when using handbrake;
When I set CPU clock multiplier to 50 and run handbrake, my cpu clock runs at 4.7GHz stable
When I set CPU clock multiplier to 49 and run handbrake, my cpu clock runs at 4.6GHz stable
but...
When I set the CPU clock multiplier to 48 and run handbrake, my cpu clock runs at 4.8GHz stable
I'm getting good 100% cpu utilisation in all cases
please help.... is this anything to do with avx ?
handbrake 1.3.3
Windows 10
Intel i7 - 9700K
Re: Handbrake cpu clock multiplier
Posted: Wed Mar 17, 2021 6:13 pm
by rollin_eng
This sounds like a bios/os issue, HB cannot change your cpu speed.
Re: Handbrake cpu clock multiplier
Posted: Wed Mar 17, 2021 6:55 pm
by Deleted User 13735
It's a mystery ...
Re: Handbrake cpu clock multiplier
Posted: Thu Mar 18, 2021 1:23 pm
by herald128bit
I have run some more tests and for some reason this does appear to be a handbrake issue...
running other applications, including userbenchmark, give full clock multiplier sustained. It appears that only with HB that the CPU multiplier drops down.
Just ran another test multiplier 51 = 5.1GHz
Games happy at this speed.
HB, drops to 46 = 4.6 GHz
Please help....!!! I am stuck on what this could be. Any possibility it could have something to do with AVX ?
Re: Handbrake cpu clock multiplier
Posted: Thu Mar 18, 2021 1:40 pm
by Woodstock
Probably your motherboard responding to a heat issue. Are you monitoring your CPU core temps?
Re: Handbrake cpu clock multiplier
Posted: Thu Mar 18, 2021 6:41 pm
by s55
Intel CPU's will clock lower when AVX instructions are used. This is the correct behaviour. Some motherboards have this as a septate AVX Offset feature. Some don't
I wouldn't recommend adjusting it. IT's offset for a reason. AVX instructions are complex and have a high power utilisation, thus heat output. We've seen a lot of people try overclock and run into hard limits trying to overclock it.
It's not uncommon to see people have to dial their overclocks back 2~300mhz or more to get the system stable for this kind of workload.