Hello everyone. I recently bought FNV on GOG and have been experiencing some major performance issues during my whole time playing it for over 40 hours now - stutters, crashes, freezes, you name it. I have tried multiple solutions on the internet, but none of them work, except for one.

I remember I first played a CD version of the game a few years back on the same computer with the same hardware. I compared the files with of the CD game and the GOG release and noticed that the CD version has a file named "d3d9.dll". As I understand, it tricks the game into running it with directx9 or something like that. I have read on the internet that it does fix all performance issues for people running the game on newer OSs (I have Windows 7, by the way).

I have downloaded the d3d9.dll file and moved to the GOG release install directory, but when I tried to run the game, it crashed before even loading the main menu. I tried doing the same with a retail copy of the game and worked perfectly, so I don't even know what the problem is with the GOG release.

Could it be that the GOG release has some different main files than the retail versions? Any suggestions would be appreciated.

While using that library, I'd try setting the game's executable to run in compatibility mode for Windows XP SP3 and as administrator.

No dice.

I tried screwing around with the different compatibility settings, but none of them work, including running under Windows XP SP3 and as administrator.

The weird thing is that Fallout 3 GOTY (also bought here on GOG) runs perfectly - not a single lag or crash. And since both Fallout 3 and New Vegas run on the same engine and are pretty much similar in almost every way, I'm completely at a loss here.

Huh, wow.

So, instead of copying the d3d9.dll file from a random source from the internet, i found the same file in the system32 folder, along with d3d10 and d3d11 files. The d3d9.dll in the system32 folder is much larger in size (2MB) than the one I have downloaded from the internet (100KB).

I copied over the .dll from the system32 folder into FNV's directory and launched the game. I was very surprised to see the game actually boot up properly. After playing for about an hour I can say that almost all performance issues are gone, but NOT completely. There's still a bit of lag here and there, but it's a far cry from how the game ran before.

I guess I can say that the problem is fixed, hopefully. But if anyone has some other advice on how to increase performance even more, your suggestions will certainly be appreciated.

Yeah, I normally don't download these kinds of files from random sources on the internet for obvious security reasons, but I was so desperate to fix the game-breaking performance issues that I threw all cautiousness out the window.

As for the mods you recommended, I think there's no need for them. My machine is more than capable of running the game even on the highest settings. I guess the problems were caused by hardware incompatibilities. I read a lot about how it is a pain to run FNV on newer machines.

But ultimately, I think I finally fixed it with the d3d9.dll file. It's not a 100% smooth, but it's very much playable now. I'm happy with that, at least.

Thank you for your suggestions. I think I can safely mark this thread as SOLVED.

One last suggestion might be the NVSR (New Vegas Stutter Remover). It's a NVSE plugin, so you need NVSE to use it. Download NVSE, copy the .dll and the .exe files into your New Vegas directory, and use the nvse.exe file to launch the game instead of the normal one. Download NVSR and check the readme.