Before updating the profile and starting the server i ran at around 300 Frames. Someone in my server does not have high end system and runs closer to 50 frames. Now that its been updated i run at 50 frames sometimes and drop to 20 frames frequently and they drop to the teens or single digits. Lowered all settings, disabled or even outright removed some mods to help and nothing changes. At the lowest setting i still run at the same framerate. No other programs are running iv made sure of that, i have triple checked the server and its settings, nothing has been changed or should be causing these drops. Im at a loss, i have had two crashes as well, if it happens again ill post up what i get

The newest update I am actually getting better performance. You can try changing mipmaps to 0 if they are not already and if that doesn't work give optifine a go but make sure to use the newest test version.