pfSense and Hyper-Threading in 2020

  • We’ve been running pfSense on a 10-year old 4C/8T beast of a rack server. According to the server’s performance tuning documentation from DELL, one should disable Hyper-Threading (HT aka Logical Processor) for low-latency applications. Furthermore, plenty of pfSense posts recommend disabling it as several daemons aren’t (or weren’t?) multi-threaded.

    What is the general advice here? Our fully utilised firewall doesn’t even break a sweat, so one might assume disabling HT could only improve our firewall’s overall performance. Curious to see what you think.

  • Netgate Administrator

    It will probably make no difference if it's not being heavily loaded. If you have a load of packages loaded that can make use of 8 cores it probably makes sense to keep them. Otherwise you can get better per core performance with HT disabled as the CPU doesn't have to switch between threads. Something single threaded like PPPoE or OpenVPN may benefit slightly from that. But if you have lots of spare CPU cycles anyway I doubt you would notice it.


  • That’s what I was thinking. Thanks so much for your answer, Steve!

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