Unexpected latency issue

I think you are looking for a new PC at this point.

I changed the GRUB file back to the original and tried one more time with the histogram. The first result shown is when I had several internet windows open, sheetcam, and 3 GLX gears. The second result shows the spike from the second I opened YouTube and clicked play on a video, Although, I'm not going to be opening YouTube while I'm doing CNC work so I don't know how practical that really is. Do you guys think the first results would skimp by providing I only used this for QTPlasmaC or is it still not looking to great?

You might scrape by if using a Mesa or Pico card, but not if you are using the parallel port. (Sorry, I have not read back to find out)

No worries. Thank you. I am using Mesa hardware. At this point I guess I'm just going to look for a good used Optiplex. At least that way I'll have a little piece of mind when running the machine. Thank you all so much for your help. This forum is awesome.

You might as well continue with what you have for now. The configs are portable. And you might find it works fine.

Make some parts, worst case you break some tools.

Update: I bought a used desktop PC (as suggested) along with a monitor, keyboard, etc. The PC is a Lenovo M93P Tiny desktop model with an i5 2.9ghz CPU, 8GB RAM, and a 256GB HDD. Surely I thought this would suffice. I always read about an older desktop being good enough to use for CNC and run the RT kernal. I went through the install process of LinuxCNC. HORRIBLE latency test results. Can you guys help me out? Now I'm just throwing money away. I have 2 GLX Gears open with a few internet windows and I can barely type this response. I have already gone into the BIOS and disabled any power saving or unnecessary features. This is the slowest system I have seen in awhile. Please help.