Try a good defrag after patch / install. It might be struggling to pull the textures from the HDD. If your are using an SSD (flash) disregard this advice.
Do you have the specs of your machine? As in more detail? Might wanna throttle back the memory OC and see if that helps.
I noticed you upgraded the motherboard from your previous rig. Did you just plug the old HDD in without reinstalling everything? While you don't absolutely have to, but if you install a new MB, it is good practice to reinstall everying (Windows basically). I do a clean wipe. It clears/prevents many headaches. I mean it is kinda having a spine transplant if you will accept that analogy. The chipsets, memory controllers, HDD controllers, sound etc... is all different. They all need new drivers, and if you just "plug and play" the drivers might crash amongst other settings.
A clean wipe might seem drastic, but what does a few hours of backing up and reinstalling everything compare to months of little problems and troubleshooting. It's just less headache overall. If you have a large second and/or external HDD it is relatively painless to back up. Even more so if you have backup software (though I don't use it since I pretty much have all the settings I need committed to memory).
The clipping issue happens occasionally, and people have exploited it to visit blocked off areas

I don't think it relates to your problems.
Good luck~
Edit: If you want, you can try driver cleaner and wipe everything and download the newest revision of all your relevant drivers... less drastic measure if you want to try that.