It’s confusing because both AMD and Nvidia call both frame gen and upscaling as the same thing.

Upscaling: GPU renders game at low resolution (eg, 720p), and then (semi) smartly guesses what’s in the pixels that weren’t rendered. You get improved framerates because the GPU is doing less work per frame. The downside is typically that the image is typically a bit blurrier, and depending on how the GPU guesses the missing pixels, you might also get ghosting, which is where moving objects leave a smear trail behind them. The general consensus is that if you plan to use an upscaler, you should only use the highest quality mode on the upscaler. Any lower and the blurring becomes too significant

Use when:

• your GPU isn’t powerful enough to drive your monitor at its native resolution (ie you were going to run the game at a lower resolution anyways)
• your game isn’t running as fast as you’d like, but turning down the settings would result in too noticeable of a drop in visual quality
• your game doesn’t support your monitor’s native resolution (common in older games)

Do not use when:

• you could turn down the settings and still be satisfied with the visual quality

Frame gen: GPU renders a frame, holds on to the frame, renders the next frame, and then guesses at what happened between the two frames. The framerate is improved because the GPU is inserting an entirely guessed frame in between every rendered frame. The downside is that because the GPU has to hold on to a frame, the latency is increased. More specifically, the time between when you move your mouse and when your camera moves will be increased with frame gen.

Use when:

• your game isn’t latency-sensitive (eg puzzle games, strategy games, some adventure games)
• you have a high refresh rate monitor (higher refresh rates typically lead to less added latency)

Do not use when:

• your frame rate (without frame gen) is below 60 fps (added latency becomes too noticeable)
• your game is latency-sensitive (eg competitive multiplayer games)

Terminology:

• AMD FSR 1: semi-dumb upscaler

• AMD RSR: literally just FSR 1

• AMD FSR 2: semi-smart upscaler

• AMD FSR 3: very slightly smarter upscaler than FSR 2, and comes with semi-smart frame generation

• AMD AFMF: literally just the frame generation part of FSR 3, but slightly dumber

• nVidia DLSS 1: semi-dumb upscaler

• nVidia NSR: literally just DLSS 1

• nVidia DLSS 2: semi-smart upscaler

• nVidia DLSS 3: smarter upscaler than DLSS 3, and comes with semi-smart frame generation

• Intel XeSS: semi-smart upscaler

Upscaling is the gpu creating a lower resolution frame, then filling in what would be there by guessing. Like, for a 4k frame it produces a 1440p frame then fills in the missing half of pixels. This gives more fps than if it did all the pixels.

Use this when you want the game to look better, but can’t handle the fps at native resolution

Frame Gen is where it guess what the next fram will look like. So it essentially doubles the frames.

Use that when your fps is too low.

You don’t need to, but you should probably turn one off. It’s fine to go over your screen fps but over twice it is a little overkill