I downloaded AMD Ryzen master for my 1900x running on an x399 motherboard.
The first time I booted the software it gave me the option to disable cores.
Now that option has totally disappeared from the software. It used to be under the speed option in the window, now the row is no longer there. There's the Speed (MHz) row and then underneath the Voltage Control (V) row, nothing in between.
I'd like to try settings with only 4 cores running, so need to fix this ASAP.