Evening all. I blew up my Win7 PC running a parallel port with Mach3. So I decided to build a mini PC running W10. Everything seems to work fine with exception of the servo spindle motor.
I have a Chinese AC servo that can run 2500rpm. I have the speed pulse coming off the motor and coming in on the BOB to the index port.

With the parallel port PC, put 500rpm, it's off by maybe 5%, all the way up to 2500rpm.

With the Win10 PC,running the same 100khz and the rpm drops to about 1/3 to 1/2 half of what I set it to. All the settings are the same, same xml file.

RPM's are verified with a infrared tach.

Just wondering what I might be missing???

Thanks
CR