Need help fixing janky terrain generation on DH 2.0.2 dev version

I plan on setting up shaders eventually using Optifine + Forge but could use some help improving performance first, and fixing the janky generation. The screenshot shows my PC specs, I think they're pretty good, but also you can see how the terrain doesn't generate fully. I've flown over multiple times with CPU usage set to max and it still refuses to load. I reloaded the save which fixed the FPS mostly and most of the ground generated, but the same spots still weren't loading. Is this just an issue with the dev version? Because I tried v2.0.1-a first and had similar problems. Also, when I loaded with the dev version for the first time I got constant 2/5 FPS, even after disabling generation, which was fixed by reloading the save. On both versions when I flew around loading chunks my game would lag and stutter a lot, even when sitting still for a while or disabling DH generation. Can I stabilize FPS without always reloading my save? I only have 2GB of RAM allocated for MC so far, if it makes a difference.