Last week we were able to run some initial benchmarks of Fallout 76 to see how it fares on various GPUs. Today, with the second to last beta and a 30GB update in hand, we hopped back in to find Bethesda's short-term fix to speed hacking. As we feared, rather than fixing the engine to properly handle higher framerates and refresh rates, a framerate lock is now in place, and adjusting FOV (field of view) is likewise disabled, sort of.
We tried editing the INI files as before, including setting them to read-only, all to no avail. The third-person FOV defaults to 80 (though you can still press and hold the middle mouse button and move the mouse to zoom out a bit more), and the first-person FOV defaults to 90. Manually setting an ultrawide or even double-wide resolution still works and auto-adjusts the FOV as appropriate:
But there's some good news, at least for now. [Credit to Super Mario in our comments, and I've confirmed this during the final beta period.] If you create a Fallout76Custom.ini file in your My Games\Fallout 76 folder, and add the following lines to it, FOV adjustments still work. Given Bethesda locked out editing FOV in other files, however, it's unclear whether this method will continue to function in the future.
[Display] fDefaultWorldFOV = 95 fDefault1stPersonFOV = 100
As for the framerate cap, it appears to be fully enforced and hard-coded into the engine. Previously, Fallout 76 would run at your display's desktop refresh rate, up to 75Hz, or half the refresh rate on high-end gaming displays (eg, 72fps on a 144Hz display). Now, the maximum in-game framerate is 63fps as far as I can tell, slightly higher than 60 in order to reduce microstuttering. That applies to 75Hz and 144Hz displays as well, though if you run at a lower rate like 98Hz you'll end up at 49fps if you set iPresentInterval=1.
Fallout 76 is set to officially launch on November 14. Bethesda might revisit the framerate lock and eventually allow higher framerates in the future, along with FOV adjustments, but given past history that's unlikely. Various iterations of the Gamebryo engine have had a 64Hz physics tickrate and issues with higher fps for over a decade. There are likely plenty of other higher priority items to fix right now.