Turning on an upscaler can make a game run dramatically faster with barely a visual penalty, or it can look worse than native resolution. The difference comes down to how the technology reconstructs an image, and which mode you pick.
If you've opened a graphics settings menu in the last few years, you've likely seen options like DLSS, FSR, or XeSS sitting near the resolution and quality presets. These are upscaling technologies, and they've quietly become one of the biggest performance levers in modern gaming. Understanding what they actually do, rather than just flipping them on and hoping, helps you get the frame rate you want without accidentally tanking image quality.
The basic trick: render small, display big
At its core, every upscaler does the same fundamental thing. Instead of rendering a game at your monitor's full resolution (say, 4K), it renders the scene internally at a lower resolution (say, 1440p or even 1080p), then uses an algorithm to reconstruct and sharpen that image up to your target resolution. Rendering fewer pixels means the GPU does less work per frame, which is why upscaling can boost frame rates substantially, often by 30 to 70 percent depending on the mode and hardware.
The hard part isn't shrinking the image, it's rebuilding the missing detail convincingly. This is where the three major approaches diverge.
DLSS, FSR, and XeSS: different engines under the hood
- NVIDIA DLSS (Deep Learning Super Sampling) uses a neural network trained on high-resolution reference images, run on dedicated Tensor Core hardware found in GeForce RTX graphics cards. It combines this AI model with temporal data, information from previous frames and motion vectors, to predict what fine detail should appear in the upscaled image.
- AMD FSR (FidelityFX Super Resolution) in its modern versions (FSR 2 and later) also uses temporal accumulation, blending data across frames using motion vectors, but relies on a more traditional algorithmic approach rather than a trained neural network. This is why FSR runs on a much wider range of GPUs, including those from other manufacturers.
- Intel XeSS works similarly to DLSS in concept, using a machine learning model, but is designed to run in two modes: one optimized for Intel's Arc GPUs using dedicated matrix hardware, and a more general version that runs on broader hardware via standard compute shaders.
None of these technologies are simply blurring the image and calling it a day. They are actively trying to reconstruct information that was never rendered, using clues from motion, prior frames, and (in the AI-based cases) statistical patterns learned from training data.
Why quality varies by mode
Each of these systems typically offers several presets: Quality, Balanced, Performance, and sometimes Ultra Performance. The names describe a tradeoff, not a marketing tier. Quality mode renders at a resolution closer to native (often around 66 to 77 percent of the target resolution per axis), so there's less to reconstruct and the result is closer to a true native image. Performance and Ultra Performance modes render at much lower internal resolutions, sometimes a third or less of the target, which frees up far more GPU headroom but gives the reconstruction algorithm much less real data to work from.
This is why the same upscaler can look nearly indistinguishable from native resolution in Quality mode on one game, and noticeably soft or smeary in Performance mode on another. The algorithm is only as good as the pixels it's given to reconstruct from.
Common visual artifacts to watch for
Because upscalers rely on motion data and information from previous frames, certain kinds of scenes are harder for them to handle than others.
- Ghosting: faint trailing outlines behind fast-moving objects, caused by the algorithm blending in stale data from earlier frames.
- Fine detail loss: thin objects like wire fences, hair, or foliage can flicker, shimmer, or disappear partially because they're too small to reliably track between frames.
- Disocclusion artifacts: when an object moves and reveals background that wasn't visible a frame ago, the upscaler has no prior data for that area and may show brief smearing or noise until it catches up.
- Over-sharpening halos: some implementations apply extra sharpening to compensate for softness, which can create visible outlines around objects, especially at Performance-tier settings.
Frame generation is a separate technology, not more upscaling
Newer features like DLSS Frame Generation and AMD's FSR Frame Generation are often bundled in the same settings menu, but they do something different. Rather than reconstructing a rendered frame at higher resolution, frame generation inserts an entirely synthetic frame between two real rendered frames, estimating what the in-between motion should look like. This can dramatically raise the frame rate counter, but it does not reduce input lag the way real rendered frames do, and in some cases can introduce a small amount of latency, since the game needs to hold frames back briefly to interpolate between them. Many implementations pair frame generation with low-latency technologies specifically to offset this, but it's worth knowing that a frame generation number on screen is not the same as native rendering performance.
Practical takeaways
- If your GPU can already hit a comfortable frame rate at native resolution, try Quality mode first. It offers most of the performance benefit with the smallest visual compromise.
- Drop to Balanced or Performance mode only if you're GPU-limited and need the extra headroom, for example to hit a high refresh rate on a demanding title.
- Ultra Performance modes are generally best reserved for very high output resolutions like 4K or 8K, where the sheer pixel density helps mask reconstruction softness.
- Treat frame generation as a smoothness feature for the display, not a substitute for real rendering performance, especially in fast-paced competitive games where input responsiveness matters.
Not all games implement upscaling equally well
The quality of DLSS, FSR, or XeSS in any given title depends heavily on how well the developer integrated it, including motion vector accuracy and UI handling. The same version of the same technology can look noticeably better in one game than another.
