Boilerplate response (updated) follows, but still applies.
All visual stuttering or "frame rate" problems are caused by the video stream having to wait for the "art assets" required to render the display OR the game writing something to disk (such as a save game file or logging). Mostly these are due to the hard disk drive being orders of magnitude slower than VRAM, with System RAM (e.g. "ENBoost") and "solid state drives" (SSDs) being in-between. There are and will always be situations where the higher FPS will drop as you decide to head in a direction the game did not anticipate and "pre-load" into video memory.
Keep in mind that this game was designed for older PC and XBox console systems, and it is now possible for your new "latest and greatest" gaming machine to be faster than it can handle. There are internal design choices that cannot be overcome. This is especially true if you are attempting to run at a "frame rate" higher than 60FPS which can introduce unanticipated problems. (If you haven't already, try locking your video card to 60FPS for FNV.) The "video pipeline" has always been prone to problems.
The following are "mitigations" that have been found to help some people.
MAJOR UPDATE: The mod FNV Mod Limit Fix has revealed that the "140 plugin limit" existed was because the game was opening 3 file handles for each plugin. The game has a hard coded limit of 512 maximum handles that could be opened at once, AND IT NEVER LETS THEM GO until it closes. (Potentially this applies to ALL files it opens.) This fix simply bumps that up to 2048 to allow for more room for file handles. This obviously has a potential impact upon any file related issues and makes it worth a try for that reason alone.
Please see the following entries under the 'Solutions to Performance problems' section in the wiki Fallout NV Mod Conflict Troubleshooting" guide if you haven't already.
* 'Issue: "Full screen mode" exhibits CTDs and stutters or micro-stutters'
* 'Issue: Lag or "micro stutters" even with "New Vegas Stutter Remover" installed'
* 'Issue: Win10 Screen tearing in "Borderless Windowed Mode"'
* 'Issue: CTD without warning, "Out of Memory error", or stops responding after the Main Menu' for other settings that can indirectly affect micro-stutter.
* There are also some NVSR configuration suggestions under the 'Issue: Game in slow motion' and entries. (These will not help with the "Tick Fix" alternative mod, but the author of NVSR now has a suggested configuration for Win10 linked there.)
* The 'Issue: What's with these Solid Green billboard signs in the distance (LOD)?' entry under the 'Solutions to Mesh (Red "!" icon) or Texture (solid color) problems' section can also help if your problems started after you installed VWD/LOD texture packages.
* If you are using CASM or some similar "auto-save" mod to manage your save game files (recommended), try increasing the "time between saves" set in the "save frequency"; and reducing the number of occasions it saves to the minimum (e.g. disable most "Autosave Events" in CASM) and see how that impacts the game seeming to freeze temporarily.
* If you have "NVSE logging" enabled (see the 'Checklist Item #4' entry in the wiki "Fallout NV Mod Conflict Troubleshooting" guide), disable it until actually needed.
(Reading from or writing to disk for any reason is the slowest thing the game does.)
The size of your image files also has an impact. Larger/higher resolution is not always "better". Please see the wiki "Display resolution versus Image Size" article.
The 'Issue: What INI edits seem to be most beneficial to performance' entry of the wiki "Fallout NV Mod Conflict Troubleshooting" guide) may also be some help. However, the above mitigations are more likely to have a fundamental beneficial effect with or without any INI adjustments, so consider them as the last resort.
As you can see, there are a number of things that can underlie your problem. If one of these doesn't fix it, I would be interested to hear about any eventual solution that does.
Edited by dubiousintent, 22 April 2020 - 02:35 AM.