Minecraft lied while minimizing?

Unzwar I wanted to ask if jmd. A solution to the following problem has.

Minecraft can be played completely normal without any laggs / stuttering, as long as it is in the foreground, but as soon as I move it to the background in full size or minimize, it starts to lay and my PC smears despite that it is relatively good. Only if I reduce Minecraft and then minimize it, I can easily continue to use the PC.

A solution would please me. ^^

I would suspect the video driver, or Java is not up to date. That it jerks while you move it is normal. Possibly. Must also allocate more RAM.