Wait, this means that all the RP I've been wasting on Hyperdrive size is useless. . . I was WONDERING why I couldn't find the hyperdrive anywhere else.
From 6.0 onwards, the hyperdrive does nothing. It was removed/diabled due to the engine changes in v6.0 and steve not knowing how to make them compatible with the new system. Pre-6.0 they multiplied the speed of your craft by a certain multiplier that I can't remember.
it's interesting outside the gravity wells of stars, that you can see with a checkbox named show hyperlimit, in the display tab. This allows to move faster from 2x to much more. Only worth it if you have a very far jump point or if you have colonized binaries or more solar system with super huge distances.