My system is a i7 6700k with a 1080 , what i can say is loading was quicker for me after the patch
First thing is this the same if playing in fullscreen (window) mode as that is how i play usually as I window key out a lot
otherwise maybe try a clean boot per this link and try a clean install of the video driver initially
A clean boot changed nothing, the game itself seems to be unsure of what it is doing as it cycles through the loading shaders part - it often starts at 1/1000 and get's to 999/1000 and then restarts etc. (Numbers aren't specific but just trying to point out what the issue is).
I have the game installed to a Seagate SSD, and have verified the game data through Origin.
The game itself ran fine before the patch but the patch has introduced this loading issue. I have also tested this with both the latest Nvidia driver (381.65) and it's predecessor (378.92) and the issue is the same.
Previous to the patch the game booted in seconds as did loading save files.
Edited to add - I play the game in fullscreen mode (no window). I use a secondary Pc to browse.
After the patch was the first time I noticed it saying "loading shaders" at all so the loading may be heavier post patch, but I only saw that message for a few seconds so something is clearly screwy for you.
So what could be the cause? You seem to have problem either writing to the disk or reading from it, but only to a certain extent. Any kind of security software could possibly cause this, and while it worked well before, the software could react differently to the patched game. Using clean boot should've worked in this case though, unless it's Windows Defender itself that's problematic.
You could try deleting shader files in case you have "temp" files that aren't cleaned up/updated properly. These are often calculated/created when you run a game for the first time or change settings, and so not necessarily part of the files that Origin checks. Though if you delete anything you should of course repair the game afterwards to make sure you have everything you need.
Another way that may clean up the shaders is if you drastically lower the graphics, restart the game and load a save, and then change the settings back and restart.
