Recommended PC configuration: CPU and Motherboard (Q1 2020)

A lower resolution may help.
One thing I have noticed on the machine I do most of my packaging and building of kernels is that a 4.19-106-rt44 kernel has given good results.
I'll give you a link to a fully installable Mint XFCE image with the above kernel and Linuxcnc 2.8 with a little mod to the build to do with docs. Linuxcnc has been built with git sources from 6 March 2020.
All Mint\Ubuntu packages were update on the day I created the image, so about 99% of the packages should be the latest.
forum.linuxcnc.org/9-installing-linuxcnc...with-linuxcnc#157411
And jump to the 9th march link.

Thank you!
But i'm trying to work on what i have before giving up.
I just installed Mate, and with that i got a quite great improvement on latency, at least when it comes to resize windows.
Now i can resize firefox with an hd video playing while staying below a 50ns jitter.
I should be plenty good enough when working with a mesa 7i96.

I got another big improvement with isolcpus=3

I think that the picture speaks for itself XD

Must have been the choice of tunes

For sure!