Fan continually running on my Mac Mini

Hi all,

I have a Mac Mini ( Late 2012 model, Silver type ). i7, 2.6Ghz with 16Gb Ram. Running HS

For sometime now the fan is continually running and fairly high.

I've tried the SMC reset, no luck.

I also think because it is running high it has slowed down the Mac, things are what i would call a little clunky.

ie: when you move say a window which is open around ( say from left to the rightside it judders, does not move in one clean motion ).

Anyway does anyone have a thought on this little problem.

Steve