I have successfully undervolted the CPU, iGPU, and CPU cache using VoltageShift on my late 2013 15" MBP running Big Sur. I had to flash a patched EFI using a physical programmer in order to unlock the undervolting which was locked with a Big Sur firmware update. If you want to learn more about...
I've got a 2013 MacBook Pro Retina and a LG 27 UD68 monitor.
I've got it hooked up with an HDMI cable and it works.
Would there be an advantage to using the Thunderbolt/DisplayPort output through an adaptor to the DisplayPort input of the LG monitor?
One possible adaptor...