Just developed a problem with viper 200s, growling/strainning during moves

My machine, except the computer, has been bullitproof for several years. My computer died and I had it seviced. The guru said it was a memory error and nothing had changed in my programs. When I cranked it and Mach3 up, I noticed that the x & y drives made sounds like they were out of tune. Very heavy growling/jercky movements. It would even fault out the drives. I've changed out the desktop 2 or 3 times with no issues on parameters. I'm wondering if I'm getting low control voltage to my boards.
Any thoughts?
i_r_

Did you run the pulse test program in the mach 3 to see how steady the pulse stream is ?

Larry

I have not. I will look up how to do such and get back to you.
Thanks
i_r_