BIOS tweaks include turning off hyperthreading, multicore scheduling, turbo boost, secure boot, unused USB ports, SATA port, HD Audio, WLAN, Bluetooth, Virtualisation. If not using HDMI port, can also turn that off.
A slightly different cyclictest, while using Mpd and playing music:
$ sudo cyclictest -t4 -p 90 -N -s -i 10000 -l 10000 -q
T: 0 (102034) P:90 I:10000 C: 10000 Min: 2003 Act: 2263 Avg: 2258 Max: 5748
T: 1 (102035) P:90 I:10500 C: 9526 Min: 2146 Act: 2913 Avg: 2343 Max: 5747
T: 2 (102036) P:90 I:11000 C: 9093 Min: 2181 Act: 2794 Avg: 2426 Max: 6335
T: 3 (102037) P:90 I:11500 C: 8697 Min: 2473 Act: 3033 Avg: 2774 Max: 5383
Have built my own RT kernel (5.10.41-rt42) and also using CPUset to optimise processes across CPUs
https://www.snakeoil-os.net/forums/Threa...-processes
and CamillaDSP for convolution (DSP)
https://www.snakeoil-os.net/forums/Threa...Correction
Plus tweaking of process priorities.