Old Games Lagging, Help Requested

So I've been trying to play some games that are a few years old now. The games are Attack on Titan 2: Final Battle and Assassin's Creed 3: Remastered (don't judge me). For some reason even though my hardware exceeds the recommended specs for both games they lag. For AoT2 it's just annoying but for AC3 it's basically unplayable. I've tried googling for an answer and what I get tells me to change 3D settings in my GPU but their aren't any settings for that and screenshots look different than what my stuff shows.

Can anyone give any advice on how to make them not lag? Both games are on Steam and I set them to use DirectX9, which helped with AC3 but not enough. While playing my GPU is at almost 100%, I don't know if that's good, bad, or normal. I'll post my hardware info in a comment. There will probably be too much info because I don't know what's important