Minecraft=memory 80-90% game! Probably Java

so...
1.when is put minecraft in taskbar... i cant play! and screen of the game are black!!
2. ncreases memory! 80-90% whhhhaaat???
3.uninstall/install dont have efect of this bug.. (minecraft+java) any version
components PC!
Geforce GTX 750 Nvidia
Intel(R) core(Tm) i7-6700 Cpu @ 3,40 GHz 3,41 GHz
8.00 GB
Operation 64-bit
SOOOO I WANT SOME HELP.. please!!!