Marioface5: There's a bug with the movement in both of these games (though not Oblivion, despite using the same engine if I'm not mistaken) that sometimes causes my character to continue moving for a bit after I've released the movement keys. It doesn't always happen, but it does occur frequently enough to be a problem. It can really mess up sneaking by making you walk out into the open when you don't mean to, and can force you to walk into traps when you should have been able to stop. In general it's really annoying. I had this issue with the Steam versions of these games, and unfortunately I still have it with the GOG versions.

Not everyone experiences this bug, but nobody seems to have a real fix for it. To be clear, I'm not talking about a very tiny delay in stopping, which I've heard is normal. The bug causes your character to move like an extra foot or two when they shouldn't.

RPGGamer67: Try to limit the FPS in-game to 60 and see if that solves your problem. The engine was not built with 60+ FPS in mind.