RTAPI: ERROR: Unexpected realtime delay on task 1

after turning off HT looks like it's running without a problem (no rtapi errors) ..

the base.time and servo.time graph are interesting .. not sure what peaks there are "acceptable" and which are not.. what is the normal timing and how to know what's ok and what's not ?

audio was disabled, ir is not there, serial I left on thinking I might need it for something (actually wanted to try some idea out but then gave up), I'll kill it too, cpu throtling and energy power saving I turned off in bios but I see that linux kernel is overriding some of those settings ( as I wrote in the first post in this thread I see in the dmesg "ENERGY_PERF_BIAS: Set to 'normal', was 'performance' and ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)" no clue why is kernel switching bios setup frmo pefrormance (everything at max constants) to "default" ... HT I like myself and would never have turned it off if I haven't found bunch of ppl saying it should be off so it's the first thing I tried now during this session and it looks like it's solving the issue .. will test bit more but if the problem is not solved I'll go further removing the gpu...

I didn't get answer to MESA thing btw, does anyone knows if this latency is affecting mesa cards too, all of them? some of them?

For mesa max 1 KHz servo thread jitter very roughly:
Position mode Stepgen 50 usec
PID stepgen/servo 100 usec
PID stepgen/servo with DPLL 500 usec

just to update thread with final findings
- disabling hyper threading solved the problem completely
- looking at the base and servo time plots shown that while I don't have rtapi errors I do have lot of jitter
- tried using the "integrated" vga but this i7 board don't have one so I replaced original HD3650 with HD6450, mostly 'cause I noticed 3650 was pretty hot (some silent edition from asus) so I put 6450, higher number, smaller heatsink (also silent, no fan), this also decreased the jitter I see on the plot and it's heating less then 3650 so winwin

so linuxcnc is running rather nicely now