Lenovo T14 Gen2 AMD - CRAZY High Latency - Am I screwed?

Hello All,

Im a first timer trying to setup linuxcnc and fairly new to linux in general.  Im hoping there is something im overlooking and my purchase wasn’t a waste but not optimistic…

I was originally going to get a Pi5 but price went from $80 to $130 locally just for the board that would have needed cost of case and screen on top of that.  Picked up the laptop below for $200 so it seemed like a sweet upgrade and saw what appeared to be success from other users on what seemed like similar hardware.  I understand that laptops are not ideal due to power saving settings built into them but I will be running a Mesa 7i96s so figured I could get away with it.  I wanted something with a bit more power as in a perfect world I WOULD like to be able to run fusion 360 on it (I know its not directly compatible) if I need to make simple tweaks to a program.  This would just save me carting around two computers.


Computer:
Lenovo T14 Gen 2 AMD
Ryzen 7 Pro 5850u (8c/16t 1.9ghz)
Radeon Integrated Graphics
16gb DDR4 3200
512gb SSD
Realtek RTL8111H-CG Ethernet


Installed LinuxCNC 2.9.8 Debian 13 Trixie PREEMPT-RT without major issue except it not finding network drivers itself.  Everything seemed to work ok but I installed r8168-dkms to hopefully prevent issues.  Get into the system and run the latency test.  Not getting any consistent results but from the latest run I got the following.

Latency Histogram Results with nobase – 2450 microseconds running 10 glxgears and a couple videos
Latency Test Results – Servo thread jitter 3,370,408ns 
Latency from laptop to Mesa card through a 3 ft cable is 0.857/0.891/0.937/0.014ms


Results seem crazy based on what I have read so I started following various peoples advice on tweaks.

Going through the BIOS its completely LOCKED down unfortunately.  There are basically no options other than security and boot options.  I went through and did everything I could but no ability to disable SMT or anything else that everyone recommended as first steps.

Walked through several videos on youtube from MrRodW on system and kernel tweaks and none of the tweaks seem to have a significant impact unfortunately.  I could get a little better but still miles off what people say is acceptable.

Changes made
Isolcpus – tried several combinations of multiple and single cpus
nohz_full – matched above changes
rcu_nocbs – matched above changes
intel_ideal.max.cstate=0
processor.max.cstate=1
idle=poll
cpupower frequency-set --governor performance

Checks:
uname -a = Linuxcnc 6.12.63+deb13-rt-amd64
latency-histogram – Note: Using POSIX realtime


So give it to me straight….  Am I screwed?

Thanks,
Looby

Probably...
But, do download and test from USB the 2.8.4 version of LinuxCNC in a live session, report back how that looks.
And from experience with many, many laptops, they either work or they do not, so tweaking might just improve things a bit, but going from 3 million to 25-50K is never going to happen.
Also, disable TPM or whatever Lenovo is calling the Trusted Platform and anything related to virtualisation.
Some ideas here:
forum.linuxcnc.org/18-computer/54369-use...mesa-ethernet-boards

No eBay APP ID and/or Cert ID defined in Kunena configurationNot being able to access the bios seems quite a handicap. Lenovo says replace the motherboard. I found some possibilities otherwise:

and
www.reddit.com/r/thinkpad/comments/13wwp..._reset_for_t14_gen2/

Hope that helps.

Ill try the other release and see how it shakes out. Its killing me because I see the T470/T480 in use in that thread and this is just the newer version of that laptop. Also I figured I was safe because this one can be bought from Lenovo with Debian preinstalled.

Sorry to clarify the bios is not password locked its just extremely limited by the manufacturer. Locked down in terms of restricted to basics.

Well Ive spent all day trying other installs or live versions and no dice. Cant get any to run live as they just hang at a blank cursor screen. Cant even get anything installed due to a "bad archive mirror" error.

Tried latest regular Debian and got that installed and then followed directions to install linuxcnc and got it up enough to latency test aaaaaand 4,550,000ns....

What causes this so I have some idea what to avoid in the future? What in the hardware would cause this?

Last ditch effort, but not far fetched: repaste the CPU.