# CPU Thread Capping issues in 5.9-RC1
**URL:** https://discourse.paraview.org/t/cpu-thread-capping-issues-in-5-9-rc1/5852
**Category:** ParaView Support
**Created:** [November 20, 2020, 4:26pm UTC](https://discourse.paraview.org/t/cpu-thread-capping-issues-in-5-9-rc1/5852 "2020-11-20T16:26:13Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@mconti](https://discourse.paraview.org/u/mconti)
#### Post date: [November 20, 2020, 4:26pm UTC](https://discourse.paraview.org/t/cpu-thread-capping-issues-in-5-9-rc1/5852/1 "2020-11-20T16:26:13Z")
Hey all, looks like the environmental variables to cap PV CPU usage have changed in 5.9, does anyone know what the new ones are?
These are the environmental variables that cap the CPU usage PV can grab, and without them it will eat up all the CPU it can (and it is usually MUCH more than it needs).
I set them in 5.8 using the simple script below, but this is no longer working and my CPU usage is out of control during testing of 5.9-rc1.
> #!/bin/bash
> NP=$1
> export KNOB\_MAX\_WORKER\_THREADS=$NP
> export OSPRAY\_THREADS=$NP
> echo $KNOB\_MAX\_WORKER\_THREADS
thanks,
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### Author:  [@ben.boeckel](https://discourse.paraview.org/u/ben.boeckel)
#### Post date: [November 20, 2020, 5:16pm UTC](https://discourse.paraview.org/t/cpu-thread-capping-issues-in-5-9-rc1/5852/2 "2020-11-20T17:16:03Z")
I believe that OSPRay has been updated between 5.8 and 5.9. I don’t know that we control what these environment variables are, so I’d check with upstream OSPRay for what may have changed. ParaView 5.9 is using v2.4.0.
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### Author:  [@mconti](https://discourse.paraview.org/u/mconti)
#### Post date: [November 20, 2020, 7:11pm UTC](https://discourse.paraview.org/t/cpu-thread-capping-issues-in-5-9-rc1/5852/3 "2020-11-20T19:11:23Z")
Okay I was finally able to figure this out after digging through the documentation a bit more.
OSPRAY\_THREADS has been renamed OSPRAY\_NUM\_THREADS in PV 5.9 and OSPRay 2.4