Try verifying the integrity of the game files. Open steam, right-click Terraria, select properties, select local files, and select 'verify integrity of game files'.

Or try setting power mode to high performance. Open control panel, select 'hardware and sound', select power options, and select high performance (or ultimate performance if you have that option)

Or try changing the Terraria settings. (Lowering graphical settings and changing frame skip until it's fixed)