Problems with minecraft?

When i turn minecraft on with my graphics card it ussually run 100-170 fps, but when i switch to dekstop and get back to minecraft the fps falls down a lot… Maybe somebody knows how to fix it?

If the FPS doesn't go back up after you start playing for a bit, it is probably a driver issue. If it does, you may want to adjust / disable the power throttling settings for the card, so it is always at full performance.

Grafic cards not suited so get a compatible one