Like the title says, ever since upgrading my monitor I've been experiencing massive FPS drops in FNV. Pretty much going from a steady 50-60 frames, all the way down to 15-20.

I've upscalled my resolution from 1920x1080 to 3840x2160, which is obviously going to cause issues with performance, however disabling enb boosts my fps all the way up to 60+ solid with no drops. I've toggled with some features, but the main offenders appear to be Detailed Shadows and Ambient, however disabling these only really boosts fps by 10-20, these doesn't explain the massive drop. Anyone had similar issues like this in the past, or is it an issue with hardware?

For reference, I'm running a gtx970 4gb with an i7 4790k quad core and 16gb of ram. Should be good enough to get at least 30 plus fps in New Vegas, even at ultra settings. ENB is definitely the cause of my issues here. I've tried scaling back to 1920x1080 and it runs at a smooth 50-60.

Any help is appreciated.

@IRORIEH Ran into a similar issue whenever I upgraded from a 1080p TV to my 4k monitor. Running the ENB extra shaders along with 3840x2160p resolution simply was too much for my measly GTX 1060 3gb. Ended up having to upgrade my graphics card to a 1080 to use my full 4k display.

Also, Fallout NV really was never made to be played at 4k. This game was developed in 2010, when 1080p was top of the line. I'd suggest running the game at 2440p at the highest if you're running an enb with it to keep it as stable as possible. I personally run my TTW playthrough with Old World Enb and 2440p resolution on ultra and have very little issues, and i only have an i5 processor.

4k resolution while running ENBs is going to destroy any video card that's only got 4Gb vram.
However, if you have not done so already you may find an answer by modifying the memory parameters in the enblocal.ini file.
there is a solid guide here https://wiki.step-project.com/Guide:ENBlocal_INI/Memory
and while it refers to Skyrim the same steps will apply to New vegas.

start with changing your ReservedMemorySizeMb and VideoMemorySizeMb and you should be able to make things run better, as it will trick the game into using your available system memory as more VRAM.
i would also agree that running the game at 2k is your best option. it may sound cool to run your game at 4K but for the VAST majority of games and setups there is fuck all difference between 2k and 4k visually speaking, and you will get much better performance at 2k resolution.

No amount of ini config will fix your fps issue of having big resolutions with ENB enabled. You're just limited to 4gb (if you did the 4gb patch) even though you have 16gb of ram or what not.

That's just how a 32bit game works. The limit is 2-4 GB. That cannot be bypassed how much you try to! It's hardcoded!

Which is why Skyrim Special Edition of being 64bit brings so much stability even though it is still a Bethesda game. That is because 64 bit = 17,179,869,184 GB of ram, imagine that.

So give it up. Downscale your resolution or disable ENB.

cheers

The GTX970 is still a good GPU for 1080p gaming. It is a matter of horsepower. 4K + ENB is too much for the 970. (I'm guessing when you're running 4K resolution you drop any kind of AA both in-game and through the ENB, if not try disabling that it might give you a slight boost).

My suggestion would be to either drop the ENB for the sake of 4K, or keep playing in 1080p with ENB enabled until you can upgrade your GPU.