Sharpening filters: CAS, NIS, DLSS sharpness and how much to use
Sharpening is a post-process filter that increases local contrast at edges to counteract the softness of TAA and upscaling; the common implementations are AMD's Contrast Adaptive Sharpening (CAS / Radeon Image Sharpening), NVIDIA Image Scaling (NIS) and the sharpness sliders built into DLSS and FSR. It costs well under 1 % of frame time but is easy to overdo, producing halos and crunchy noise.
image sharpening · CAS · RIS · NIS · sharpness slider
Key figures
From the FPSHQ database, as of Oct 15, 2026
Why modern games need it
Temporal accumulation averages samples, and averaging is a low-pass filter: fine texture detail loses contrast even when the image is technically full resolution. Upscalers add another layer of softness at lower internal resolutions. A sharpening pass restores the perceived detail; CAS is "contrast adaptive" because it sharpens less where contrast is already high, which avoids the halos of classic unsharp masking.
Implementations
DLSS 4 output is sharper than earlier versions, so many players lower or disable extra sharpening after the update.
| Filter | Where | Notes |
|---|---|---|
| AMD CAS / RIS | in-game (FidelityFX CAS), driver (RIS), ReShade | adaptive, open source, any GPU |
| NVIDIA Image Scaling (NIS) | driver, in-game | spatial upscaler + sharpening |
| DLSS sharpness | in-game slider | removed from DLSS 2.5.1+; use NIS/driver instead |
| FSR 2/3 sharpness (RCAS) | in-game slider | tuned for the upscaler output |
| Driver "Image sharpening" (NVIDIA) | per game | works for any game, includes HUD |
How much is right
Sharpening has no effect on FPS and no effect on latency, so it is purely a taste setting.
- Start at 20–40 % of the slider; move up only if the image still looks soft at the monitor's native size
- Signs of too much: bright halos on edges, visible film-grain amplification, "oil painting" look of foliage
- At 4K you need less than at 1080p; with an OLED the perceived sharpness is higher so lower settings suffice
- Sharpening cannot recover detail removed by low texture quality or missing anisotropic filtering
On your PC
Enter your GPU (and CPU) — we calculate the effect of "Sharpening" with the unified FPSHQ model using Cyberpunk 2077 as the example.
Save your PC in the account · Detect hardware with the app · Unified FPSHQ model estimate, not a measurement.
Where to use this on FPSHQ
Forum discussions
What is Sharpening?
Sharpening is a post-process filter that increases local contrast at edges to counteract the softness of TAA and upscaling; the common implementations are AMD's Contrast Adaptive Sharpening (CAS / Radeon Image Sharpening), NVIDIA Image Scaling (NIS) and the sharpness sliders built into DLSS and FSR. It costs well under 1 % of frame time but is easy to overdo, producing halos and crunchy noise.
- games with DLSS in the catalog
- 182
- games with FSR
- 382
- Quality gain (model)
- +35%
- Performance gain (model)
- +85%
FAQ
Does sharpening reduce FPS?
What sharpness value for DLSS/FSR?
CAS vs NIS — what is the difference?
Why does the image look grainy after sharpening?
Sources
- AMD GPUOpen: FidelityFX CAS (2024)
- NVIDIA: Image Scaling (NIS) (2021)
FPSHQ Team · methodology · methodology · Updated
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