Can better thermal paste lower my temps?

I recently bought an i7 4770 and installed it with the intel stock cooler and cheap thermal paste (1,7 W/mK). In games it gets over 80°c. Could I get better temps with better thermal paste or do I have to upgrade my cooler?
Intel stock coolers aren't good coolers, especially for gaming. Pretty much every aftermarket cpu cooler comes with a small tube of decent thermal paste. What country are you located and what PC case do you have?