Does disabling rendered unload it from memory ?

i’m scripting a dynamic terrain loading thing and i basically disable the mesh renderer component of the gameobject if it’s not withing the draw radius . Am i doing this correctly ? does disabling the renderer component unload it from the memory ( ram and vram ) ? does this improve the performance of the game ?

It is still in memory. If you are only disabling it when the camera is not seeing it, then it is unlikely that your disabling the renderer will have any positive impact on performance. Unity already culls object out that are not seen by some camera.