Skyrimnewbieplayer

I am getting low fps in skyrim without any enb and graphical mods.I got 20 - 50 fps.But my skyrim is highly modified. My specs i5 3450 3.5ghz 1tb 2.5 inch 7200rpm 1tb 3.5 inch 7200rpm sapphire r9 280x ghz edition corsair vs550w 8gb 1600mhz ram Windows 10