Astro HQ

Astropad running slow with external monitor attached

Hello everyone,

Recently, I’ve had problems with using Astropad connected to an external 4K monitor, creating lag that makes the experience virtually unusable.

The computer I use is a 2014 15" rMBP with the discrete Nvidia GT750M graphics. For the most part, I don’t believe I’ve had a severe impact on performance from the monitor, and I was even able to complete most of my paintings with Astropad reading directly from that monitor. Now however it doesn’t seem to work and I keep it unplugged. There doesn’t seem to be this lag reading from the built-in display.

Is this an Astropad bug that can be fixed? Or is it my computer’s limitation in some way?
I’d really like to use the monitor to paint because it has so much screen space, so would appreciate any help.