Choose between two PC's, both have issues

Hey there,

I'm currently trying to set up a PC for running LinuxCNC via ParallelPort. I have these two lying around:

1. Computer 1: AMD Sempron 140, Gigabyte GA-M61PME-S2P: Screen freezes when running the automated latency testing script. When run glxgears, video and browsing around, I get base thread max jitter >50k ns and based thread >130k ns
2. Computer 2: AMD Atholon Atholon 64 X2 4400+, ASUS M2N-MX SE: USB not working properly, I can install using keyboard via graphical installer, but when booting into linuxcnc, both keyboard and mouse don't work, tried different usb ports. Logs when booting show entries like "usb 2-4: device descriptor read764, error -71"

Both with 2.8.0 and PREEMPT Kernel and install of linuxcnc to disk. I tried booting 2.7.14 RTAI from DVD for computer 1 and it gave me similar latency.

Computer 1 seems more promising to me since it's a single core and USB works. Any idea why the screen freezes when running the automated testing scripts? Otherwise it seems stable.

Any feedback would be appreciated.
Thanks!

Computer 2:
Enable USB legacy support in BIOS.

Thank you for your reply.

Computer 2: Legacy USB Support is enabled, see attached picture.



I also ran memtest86+ on all RAM and there are no errors. Was thinking an error in RAM might have caused the instability on computer 1. Check the second picture for how the screen looks when it freezes when I run the automated latency check on computer 1:


Maybe it's the internal GPU on computer 1 that's somehow broken?

johanneshk wrote: Maybe it's the internal GPU on computer 1 that's somehow broken?

Yup, that should be it. Find an old GPU and see if it works, preferably Matrox G400 or 450, or ATI/AMD.

I found some USB to PS/2 Adapters so I could run the test script on 'computer 2' as well and it gave me similarly bad results as computer 1.

Regarding GPU: Neither computer has an AGP slot, so I cannot test a G400 or similar (?).
I'll play around some more with the configuration and BIOS to see if I can get somewhere. I do have a Quadro 4000 lying around that I could/will try.

CNC is coming together so now I want to make some progress on the computer side as well.

Here's the result for the latency test script for computer 1 after putting in the Quadro 4000:

Seems like I'm on the right track now (?).