Why is Hitfilm Pro so laggy?

derickdd111 Posts: 2 Just Starting Out

So, as of yesterday, I purchased hitfilm pro as I've been using Hitfilm express for 4 years and have loved it. However, I'm encountering frame rate issues within the editor itself which makes it almost impossible to edit. To clarify, when I play clips within hitfilm itself, i have virtually no frame rate issues even in when in full quality mode. The issue I'm experiencing is whenever i try and do... anything. Setting a keyframe takes, no kidding, 3 entire seconds to process and I have no idea why. The video I'm working on was doing absolutely perfect in hitfilm express; no issues whatsoever- but when I imported the project to hitfilm pro, it operated very poorly. Any help would be greatly appreciated. I know it's not my pc as the video I'm making is very similar to the countless other videos I've made within Express.