Lagging when 'make RunRelease' is active

Hi all,

Firstly, loving openFrameworks so far. I’m going through the tutorial (2D Graphics and noticed that whenever I run the program using make runRelease my laptop slows down considerably until I exit. Typing gets laggy, and the screen feels like it’s slow to refresh. The problem is alleviated when I exit the program, however. Does anyone know why this may be happening?

OSX High Sierra (10.13.3)
oF 0.9.8
VS Code 1.2.1

Thanks in advance!