Nvidia Noise Reduction
Nvidia Noise Reduction 720p
While you can use something like MadVR to improve video quality, you should also make sure that you are enabling Nvidia's video enhancements which can make a large impact in terms of improving video quality. The impact on performance is minimal if you enable Nvidia's video enhancements, so I suggest utilizing these enhancements whenever possible. Noise Reduction and Edge Enhancement work well together, especially around the 30% mark.
For this round of comparisons I am only using Noise Reduction in the Nvidia Control Panel. I set Edge Enhancement to "Use Player Settings". I then played a 720p video and raised the slider for Noise Reduction by 25% intervals, starting with 0%.
The only real difference that I noticed was that higher noise reduction settings actually made the images look more noisy. Once you set noise reduction above 75% the video will sometimes look kind of strange. Not sure what causes this exactly, but I would cap the noise reduction to around 60%. Every video will be a little different, so test out a few videos before you decide on what to set here.
Noise Reduction and Edge Enhancement can be found in the Nvidia Control Panel under the video settings.
Noise Reduction 0%
Played using MPC-HC with the CUVID Video Decoder enabled, using default MPC-HC video renderer for the sake of having a baseline configuration starting point. I set the noise reduction slider to 0% for this screenshot.
Noise Reduction 25%
Using the same settings as mentioned previously. For this screenshot I raised noise reduction to 25%. If you look closely, there is a slight difference, but it's so small that I can't really tell the difference between 0% and 25% noise reduction.
Noise Reduction 50%
Again, even at 51% reduction, I don't see a massive difference in noise reduction, then again, the video already looks fine so there may not be much to improve on.
Noise Reduction 75%
Noise Reduction 100%
The video starts looking a little crazy once you raise noise reduction to 100%, sometimes you will see yellowish blobs and strange artifacts. I do not suggest setting noise reduction past 75%, personally I leave it at 30%.
Nvidia Noise Reduction Summary
There's really no reason to set Noise Reduction past 50%, in most cases video quality either degrades after 50%, or the difference in quality remains the same. Personally I use 30% Noise Reduction along with 40% Edge Enhancement. Less seems to be more when it comes to Nvidia's video enhancements.