Spent a few hours last night doing side quests in Whiterun then went and met the priests on the mountain.
Having a slight issue where the FPS will bomb down for a few seconds then catch up again, going to try forcing Vsync in Nvidia control panel tonight and see if that helps.
I don't know if it's just because I haven't played in years or I've been spoiled with The Witcher 3 but the horse even when sprinting on Skyrim seems slow.
http://www.nexusmods.com/skyrimspecialedition/mods/2003/?