Game runs in max 50 FPS with 6GB of RAM allocated from launcher and in High Priority. Launcher is set to use the High Performance Nvidia Graphics Card. Game's settings are:
Particles minimal, View distance 8 chunks, Everything off, Mipmap 1, FOV 90.

As a comparison, Version 1.8 modded with high resolution shaders runs at 60fps, and a 1.12 modpack from FTB with more than a hundred mods can go up to 90 fps or more with 6GB of RAM and Above Normal Priority.

Game lags, has lag spikes, stops responding, doesn't load chunks efficiently. Invisible boat upon exiting, making it glitchy, rarely character dies from falling while stuck in the bugged boat. World Generation makes pools of lava in the Frozen Biomes that are hidden underneath floating snow patches, lost a Hardcore Character in such a happening. Sometimes going into third person allows you to see through blocks at certain angles. Creeper explosion bug, as using a diamond armor can't save you from a creeper. Most strange is the spawnrate, really high on low local difficulty values, plus mobs can spawn so close some even spawn on top of you. Sometimes while swimming Character gets stuck at the edge of the water, needing to submerge, and try to get out of water again.

I love Minecraft, I really do, been playing it for a long while now, but it was never supposed to become a high end computer needy game. Please, stop releasing Beta versions with Alpha credentials. I see minecraft everywhere and I am happy to have been in this community since it came out. Hopefully things will get better and brighter. Aether is waiting for all of us!