My Apple MacBook Pro "Core i7" too slow

Dear All Support,

Please help my apple macbook pro core i7 CPU 2.3, Ram 4GB Screen 15 Inch Mid -2012

Got too slow.

I have install parallel desktop to run Windows 7 on Mac OS.

But Sometime in mac and win7 is much slow and sometime mac slow all time.

Please give me solution, what is the problem? I need to upgrade RAM or what? if too slow like this Apple no meaning, I will swap to other model.

regards,

Piseth