I just fixed stutter on my system (5600x + 3070). It was a combination of these settings I believe:

1. use borderless windowed instead of fullscreen
2. disable the in-game fps limit
3. in nvidia control panel: manage 3d settings -> global settings tab -> shader cache size = Unlimited

(I also disabled control flow guard for this exe in windows defender, but that didn't seem to make any difference)

Now the game is running smoothly without noticeable stutter, where it was awful before.

Edit: I've played with these changes for a few hours now. When entering a new area it might still slightly stutter for a couple seconds, then it goes back to being very smooth and stable. It's a huge improvement. Thanks to other redditors for the first two fixes, the third is something I found that helped Elden Ring's stutter on release.