important notes for latency tweak in modern pc

i was testing with rt kernel and jessie and i noticed couple of points that have very good effect.

1. dual channel momery
2. momery voltage tweak (very large impact)
3.enable speedstep or turbo
4. enable usb 3.0 (disable it will give 5.0ns more)
5. reduce the memory of the integrated gpu i use 64mb
6. don't disable audio from bios
7. disable KVM
8, disable and enable LPT from bios and try and choose different irq
this is applied to J1900 asrock latency never pass 4.3ns and 3.9ns for servo thread
also i try H110 asus ddr3 +G4400 and result was better than the j1900 just the motherboard dead from short before i finish tweaking

Hi taloot,

thanks a lot . I bought the ASUS H110-Plus (with parallel port) an on board graphic with 2x4GB DDR4 Ram and Intel G4400: it works perfekt for me. With the BIOS defaults (except secure boot) i have a max jitter of 21000

The Intel Pentium G4400, 2x 3.30GHz is without hypertheading, but that's better for linuxcnc

I don't test point 2 7 or 8

I bought Mini PC without fan with Intel J1900 processor on board with 4G RAM.
I disabled memory save in bios and reduced video memory size to 64Mb, but unfortunatly have very big latency (213000). I want to use this PC with 7i95 ethernet board

Try disabling the Cstate or set it to 1.
I had good luck with one of these but cannot get others to work due to issues with the Baytrail chipset and Linux kernel which remain unresolved.

I've disabled everything I could )))
And get result of 30 000 latency. Once only after long time of unsued working it jumped to 300 000 of latency.

I see somebody use histograms for latecy tests but I don't know what that program is.
I think with Mesa ethernet board it will work fine, more over for this task I plan to do. But standart PC's are give much better results.

I bought this PC because it's fanless, it will work in extreme environment, so standart will die very quickly.

In a terminal:
latency-histogram --nobase --sbinsize 1000 --show