Bob's Hotbar Optimizer removes the delay between switching hotbar slots that Minecraft has. This is done by making Minecraft process switching slots as soon as it receives the input. Normally, it waits until the next tick. Minecraft's slot processing works in a numerical order, from 1 - 9. If you're on slot 9, and want to switch to slot 6, you must wait for it to be processed in the next tick. This can be annoying in PvP as well as other situations.
