I am having some similar issues on my 64 bit system. Both graphics and sound stuttering that builds up until the game can no longer be played. I have tried every fix I could find suggested in the forums here and on Steam to fix the issues but none have worked. I can play in compatibility mode but that is 32 bit and will not take SMAPI. Part of the reason for update 1.5.5 was openly stated to make things easier for modders to use. So using mods or playing vanilla is a choice the developer seems want to be built into the game. I am hoping there is a fix soon, even more I hope a simple acknowledgement of the issue. I miss my automatic gates. :)