After testing AMD's new Radeon Image Sharpening feature, we ran even more tests. The first article is definitely worth reading if you missed it, as we were mainly interested in what Radeon Image Sharpening (RIS) looked like compared to a native presentation and how effective it was to post-process an upscaled image to to see it nearby. indigenous. The main focus of the test was on how RIS works compared to Nvidia's DLSS and whether the two technologies can actually do the same thing, although they work differently.
We came to the conclusion that RIS DLSS is superior in image quality and very effective in post-processing, for example in a game rendered at 1800p to get very close to its native 4K presentation. With a negligible impact on the performance of Navi GPUs, this is a pretty compelling feature.
But we haven't covered every possible angle in this article. Radeon Image Sharpening is not the only way to sharpen a game after the process. Reshade is a very popular tool that can be used for all types of post-processing, including sharpening through various techniques. Nvidia has its own sharpening option, which is also included in the customization tools for freestyle games.
Nvidia Freestyle is marketed very differently than Radeon Image Sharpening. Unlike AMD, Nvidia does not suggest using sharpening with down-sampling the resolution to get performance benefits. Mostly because they have DLSS for it. But we'll look at how it is structured in this article.
The other major new development is that the CASD filter (Content Adaptive Sharpening) used in RIS has been ported from AMD to Reshade. This was possible because CAS is included in AMD's open source FidelityFX toolkit and it was apparently easy to port to a reshade effect. Now we can see how CAS works on other GPUs and whether it actually makes sense to limit AMD RIS to their new Navi GPUs.
For this new test, we would like to compare Radeon Image Sharpening and AMD's CAS algorithm with several other sharpening options available today, including Nvidia Freestyle and two popular filters available in Reshade: Lumasharpen and Adaptivesharpen.
In addition to the images in image quality offered here, you can watch the video from Hardware Unboxed (embedded below) in 4K quality from YouTube to get the best possible representation of the game graphics. For all screenshots, you can click it to view a larger 4K version of the same image.
We'll start with Metro Exodus as it offers a good combination of 3D elements, textures and text. A closer look at these images immediately reveals that each sharpening filter has its own style and manipulates the image in different ways. In some ways the end result is similar for all filters, in others there are differences.
Reshade's Lumasharpen in its standard configuration is the most subtle of all filters. It slightly sharpens the image, clears it up a little, and doesn't introduce many artifacts. If Metro Exodus uses a sharper temporal anti-aliasing method, playing with Lumasharps is probably what I would expect.
Radeon Image Sharpening is a significant improvement over Lumasharpen. In some ways, RIS is just as subtle as Lumasharpen, for example in the fibers on the sweater on the right. Both look similar. For the New Game texture, RIS is a slight improvement without introducing a lot of halo or artifacts. But for the map in the top corner, the overall texture with RIS is clearer compared to Lumasharpen, and in such areas the AMD algorithm has a clear edge.
Then we come to Reshade's adaptive sharpening, which is much sharper in its standard configuration than Radeon Image Sharpening. However, it also has a lot more artifacts. Take the continuation text on the CRT screen. This should be a bit blurry as you can expect from this kind of display in the game world. But adaptive harping doesn't know and tries to sharpen what only this strange block-like artifact leaves behind. This occurs with a lot of sharpening throughout the image and you get haloing.
For me, Nvidia Freestyle looks most similar to Reshade's adaptive sharpening. If you set freestyle to 50% sharpening, many of the same problems will arise as with adaptive sharpening. The text in particular seems overused with a slight halo. In the meantime, the card is sharp, but not as sharp as Radeon Image Sharpening.
Now Freestyle has a sharpening strength slider, so I've reduced it to 25%, but it's just not as good as RIS. It's basically a less sharp, toned-down version of 50% that actually loses the "sharpness" edge on RIS, while still looking a little overworked in some areas.
In our opinion, at least in this game with a native 4K resolution, Radeon Image Sharpening has the best display: sharper than Lumasharpen with similar artifact treatment. However, this is only my opinion. You can look at the pictures yourself and come to your own conclusion, which looks best.
We also wanted to see how each of these filters handles resolution downsampling, and for that we have The Division 2 with 4K and a 75% resolution scale. This game only requires subtle post-processing, so Lumasharpen is really good here. Adaptive sharpening is again too sharp in my opinion, while the fight between Radeon Image Sharpening and Freestyle is interesting.
RIS is superior in some areas. Here, for example, the text "USA" is treated better in the crashed plane and with fewer artifacts. However, Freestyle handles some removed fine objects better with a more fluid presentation that is less jagged. RIS treats the UI elements better. So we suspect that no filter is really the perfect solution.
Next we have Resident Evil 2, the most blurry game in the series, and one where you can't use freestyle, more on that. Again the same problems that we have already discussed: adaptive sharpening is too sharp, Lumasharpen is a bit soft, Radeon Image Sharpening is exactly in the middle. We messed around with a higher setting for Lumasharpen, and although this improved detail is closer to RIS, it didn't take grain into account in this game or in RIS. Not that this is overly visible in this footage thanks to compression.
Finally, we also wanted to show some examples from Hitman 2. There are a lot of glow and flower elements in this game that Reshade's adaptive sharpener doesn't do nearly as well as RIS or Lumasharpen. Overall, RIS is sharper, but if we raise Lumasharpen to a level similar to RIS, it's not so good to reject these elements. So we think that overall RIS is still the best filter.
Impact on performance
When testing with Resident Evil 2 using the 4K graphics priority set on a Radeon RX 5700 XT, you can see that RIS has little impact on performance: no difference to average frame rates and a negligible drop at 1% lows.
Reshade's Lumasharpen filter had a slight drop in performance of around two percent. The sharpest filter, Adaptive Sharpen, has a greater loss of performance. Average frame rates fell 5 fps or 9 percent, with a similar decrease to 1% lows. Not good for a filter that I personally didn't like so much.
What about Nvidia Freestyle? We cannot use Resident Evil 2 for a performance comparison because it is not supported by Freestyle. So let's switch to The Division 2. Here we see a similar story for the Reshade filter of the RTX 2070: Lumasharpen is around 3% drop, while adaptive sharpening is around this 10% mark. Freestyle is also performance intensive and lowers the frame rate by about 4 fps, which is a 12 percent reduction.
The Radeon sharpening in Division 2 again shows a negligible difference in performance at 4K within the error limit. The RX 5700 XT does the adaptive sharpening of Reshade fine here with a 7% drop in performance, but there's no reason why you'd prefer this over RIS, which is basically free.
The next question concerns Radeon Image Sharpening's Reshade port, also called Content Adaptive Sharpening or CAS. This works just as easily as any other Reshade filter after you download and install it. In my tests, I found that a setting between 0.5 and 1.0 is representative of the strength that AMD uses for the filter. It is interesting that you can adjust the strength with Reshade, while there is no adjustability with RIS. However, I was delighted to discover that this Reshade port from CAS appears to be essentially identical to RIS from a visual point of view.
AMD did not lie when they said that RIS uses GPS optimizations to basically not slump performance on their latest GPUs. Test Reshade CAS with a Vega 64 card, and the drop in performance lies between Lumasharpen and adaptive sharpening. It was a 3% drop in Resident Evil 2 and a smaller 2% drop in The Division 2. Not outrageous, but a drop is a drop.
The same applies to the use of Reshade CAS on a GeForce RTX 2070, since you can of course use Reshade filters with any GPU. Approximately 4% drop in performance using the effect in Resident Evil 2 and the same effect in The Division 2.
Regarding the image quality, Radeon Image Sharpening or CAS gave me the best presentation of all the filters that I looked at and played around with. The default settings of Lumasharpen are somewhat weak. If you turn it up, artifacts are introduced that are better managed by RIS.
In the meantime, both adaptive sharpening of Nvidia Freestyle and Reshade are too strong, and optimizing these filters does not offer the same balance between sharpness and artifact reduction as CAS.
However, this is only a subjective analysis, so you can see which technique you prefer. For many people, everything looks pretty similar. In this case, it doesn't matter which filter you use for sharpening.
What is not subjective is the power part. It is clear that sharpening Radeon images on Navi GPUs is essentially free. Lumasharpen was also underperforming, while surprisingly Nvidia Freestyle and Reshade's adaptive sharpeners showed a relatively small but constant loss of performance.
Apart from comparing image quality and performance, each sharpening technique has its own limitations and usability problems. This is important to take into account in the overall picture …
Radeon Image Sharpening was developed exclusively for AMD Navi GPUs and only works in DirectX 9, 12 and Vulkan titles. Based on what we saw with the port from CAS to Reshade, there is no reason why this restriction should exist. The filter should work in DirectX 11 games and also on older GPUs like Vega. We believe that RIS should be available to all AMD GPU owners in all games. I hope this becomes a reality.
At the moment we have tricks like using the Reshade port. However, this is far less user-friendly than Radeon Image Sharpening, a simple driver switch that just works. Reshade requires installation per game. For us enthusiasts, this is a fairly straightforward process, but for casual users it is not as easy as pressing a button. You also have to hope that Reshade plays well with the game in question. Especially during my tests, I had trouble getting it to work with Hitman 2, where there were no issues with RIS, for example.
Therefore, Reshade's advantage is compatibility with a wider range of GPUs and games, and the ability to change the amount of sharpening applied.
Nvidia Freestyle has a number of problems. It works with Nvidia GPUs and if it works, it works well. However, there is a whitelist of games it works with, so titles like Hitman 2 and Resident Evil 2 are not supported, for example. Nvidia needs to open this to work with all games and not limit it to an admittedly decent but clearly not comprehensive list. Nvidia has the advantage of freestyle when working with DX11 games, but also offers a drop in performance for only modest visual quality compared to CAS.
After testing freestyle it is clear why Nvidia has chosen DLSS to downsample the resolution. Nvidia's freestyle sharpening filter is not free in terms of performance, so DLSS is better in terms of performance compared to image quality. In the meantime, RIS on Navi is essentially free and of better quality.
Although this entire ecosystem is a bit messy right now, I think this type of technology has a bright future. If we can get AMD and Nvidia to offer CAS-level driver functionality with minimal impact on performance in all games on all GPUs – which seems to be possible – the doors will be available for downsampling with usable resolution and a sharper anti- Open aliasing after the process and overall just a better gaming experience.