I've been using Lossless Scaling with a Dual-GPU setup for a long time now.
The last version that was launched was about a month ago (July 2025) and the quality increase is now considerable compared to the last post being made here.

I'm using it like this:

My RTX4060 as Video processor, using SVP + Optical Flow for the output at 48 FPS
My RTX 3090 Ti as Lossless Scaling GPU with 100% Flow Scale at 2X, Max Frame Latency 10 and  Sync Mode Vsync, this gives the absolute best results.

Since I'm using a dual GPU setup I can also add RTX-HDR to the video output.

The image looks absolutely amazing.  I won't say it's RIFE level but it's pretty close and the artifacts on the side of the screen are mostly gone, this is credit of the new update that we've received that added the "Performance Mode" for LSFG 3.1

You need to know how to mix those 2 technologies together to get amazing results. 
I also think you need 2 GPUs to make it as one GPU alone for all of these processes is a little too much, unless you have an RTX 4070 Ti or better

You should try it again.

Does it smooth it out? Yes!
But does it do a great job doing it? Not so much currently.
If u check this panning scene from the start with LSFG:
https://drive.google.com/drive/folders/ … nG0qJnlw4I
You can notice how even if you see that everything goes up, LSFG does not know the direction of the movement.
So it will create artifacts on left/right side of the screen where the stars teleport left/right/up/down around their initial positions instead of going up.
This looks horrible and really confusing and makes me always pick the Automatic Interpolation which simply pans the scene up.
RIFE is on another level, it somehow identifies the objects and generates new frames based on where the objects will move next, making the movements more accurate than Automatic.
Pick what u think it's best.

Ah yeah I see what you mean.  Even without RIFE, SVP handles that better alone than with LSFG piggbacking off it.

Now that that's out of the way, has anybody else experimented with combining the SVP and Lossless Scaling on pc before? I was tinkering around with them this morning and I'm getting probably the best looking 4k HDR performance I've ever had (not sure how it compares to RIFE engine since I can't seem to get any type of smoothness out of that in 4k).  I use a scene in Avatar (2009)[extended] (time-02:27:25) as my 4k HDR test footage on Plex since there's a bunch of color and motion going on, and with my previous settings I was able to hit about 90fps but it still had noticeable artifacting at the edges and on characters at times.
(2:27:55 at 90fps)

But by adjusting settings and lowering the fps conversion to 45, I'm able to eliminate most of the artifacts and use Lossless Scaling frame generation feature to triple the frames to about 170fps (my tv only is only 120hz so I can't notice anything more than that).
(2:27:55 @ 45fps w/LSFG 2.3)

Obviously I can't show you how LSFG affects the video with screenshots, but from what I see, even though it may not be hitting 120fps it is noticeably smoother than at my 90 fps settings.   If you have Lossless Scaling, toy around with your settings and see what you think. Am I crazy, an idiot or blind? What I do know is that LSFG smooths out the video playback even when SVP is disabled (24fps becomes 96fps) so if what I'm witnessing is accurate, it can work in tandem with SVP to get better perfomance while eliminating artifacts.

My specs: 
Ryzen 9 5900X
EVGA 3080Ti
32.0 GB DDR4 RAM

My settings:
Native SVP 90fps: https://i.ibb.co/p1pjLP2/Screenshot-native.png
Lossless 45fps: https://i.ibb.co/d0qsGxt/Screenshot-lossless.png