The lag do not depend on render distance and stays same on different distances set. Powerful tool - in example efficiency axe. Not using mods.
Game runs very fast - 40-60 fps everywhere (even in nether, even with fancy lighting and advanced opengl it stays 20+ fps) - only when getting close to large amounts of leaves it goes to 20 fps. Starting punching trees gives a lag 2-6 fps.
Anywhere else it goes 40-60 fps - fighting large amounts of mobs, running fast large distances, even setting a lot of fire or detonating lots of TNT it goes well.
It also happens to entities such as villagers.
It was still a concern 1.4.5 but I upgraded my hardware since then and I can't check this out again any more.