Temps will depend on what case your using, how many fans you have, what CPU you are using, how many graphics cards and what graphics cards you have, what cooler you have, what thermal grease your using, if anything is overlooked and what your ambient temperature is. So it is very difficult to tell you what temperature you should be running at. Saying that a drop of 6 degrees c is very good for changing thermal grease and 49 is a perfectly safe temperature to be running at.
to better understand where you are coming from we need to know what PC you are using. Did you build it? OEM? Have you cleaned it lately? 49/55 is actually kinda high for internet browsing. Nothing that is conserning, but higher than what I would have expected.