Why run a game slowly at a high resolution, when you can instead run it faster on a low
resolution that closely imitates the look of a higher one?
That’s the idea behind upscaling. Nvidia uses DLSS, AMD uses FSR, and the game Necromunda:
Hired Gun is one of the first games to feature both, which is REALLY exciting because now
we can finally compare these 2 different upscaling methods directly, in the same scenarios.
DLSS is the more intelligent upscaling method- it renders at a lower resolution, then builds
the image up over many, many frames, then uses motion vectors to try and keep it all
in the right place should there be any motion. However, it requires a lot of work to be added
to a game, and only Geforce RTX cards are allowed to use it.
FSR is AMD’s answer to DLSS. Much like DLSS, it uses a lower resolution image, but unlike
DLSS, it doesn’t use motion vectors or anything like that- it uses a nicely calibrated ‘stretch’
effect to keep the image as sharp, yet as smooth, as possible. You can see how it compares
with other stretch effects here. In the process, it DOES act like anti-aliasing- those edges
look a lot smoother than native’s are. But as you’ll see in the comparison shots for
this game, it retains some of the weakness of Temporal AA, which is presumably being
applied to the screen before FSR upscales it. So while its workings aren’t as ‘advanced’
as DLSS may be, the benefits are that it’s very easy to add to any game, and that anybody
with a semi-modern graphics card can use it. So both have their place, but in this video
I’ll be trying to compare them directly. This is a daunting task, and one that won’t
please everybody. But I’m going to try anyway, because I’m awesome. And because I’ve
been disappointed by everybody else who has tried so far.
FRAMERATES Firstly, we need to test how quickly all of
the different modes run. We can’t just compare ‘Quality’ setting of DLSS against ‘Quality’
setting of FSR, because that’s meaningless if they run at different framerates, and display
different quality results. I don’t know enough about FSR’s implementations just
yet, but I do I know that Nvidia adjusts DLSS’s base resolutions on a per-game basis. Which
means we’ll just have to benchmark each and every preset to see how they compare.
At 4K, maximum settings on a Ryzen 3700X and Geforce 3080, I got these framerates. But
I’m not happy with this because it’s evident that the game gets CPU-bottlenecked at the
higher performance settings. So I did it all again at some ungodly resolution
like 5760 x 3240 where it definitely WAS always GPU-limited, and these were the results. I
am confident that FSR’s top Quality setting runs slower than DLSS’s top quality mode
does, but below that, the tables turn, and DLSS’s framerate relative to FSR’s drops
off the further you head towards the top performance settings. Now hold your pitchforks- this doesn’t
mean that one is ‘better’ than the other. It just means they could be running at different
base resolutions. We’ll need to know how good each of these modes looks before we can
draw a conclusion from this. But what we CAN know already is: provided
you’re GPU-bottlenecked, ANY DLSS or FSR setting will deliver a massive performance
boost over native resolution. But don’t go too far with it! Don’t assume that using
the fastest Performance or Ultra Performance upscaling settings will give you better framerates.
Even at 4K, I started running into CPU bottlenecks in some locations. For instance, DLSS Ultra
Performance sometimes didn’t run any faster than DLSS Performance mode did, nor did FSR
Performance run faster than its balanced setting. But while they didn’t run any faster in
these spots, they still looked markedly worse. So don’t go too far with the upscaling,
and always be aware of whether your PC is CPU or GPU limited, because that will dictate
the settings (and resolution) you should be gaming on.
VISUAL QUALITY While DLSS and FSR both try to upscale the
image, they go about it in different ways and so their results are extremely different.
BECAUSE they both operate from a lower resolution, however, there are some things that WILL look
worse with either of them enabled- in this example, you can see that volumetric lighting
operates at a lower resolution. Which isn’t a weakness of their upscaling- merely a symptom
of their lower base resolution and the way in which the game’s engine operates. I also
noticed decals fading out sooner at DLSS Ultra Performance mode. Again, it’s hard to blame
DLSS here- I’m sure the decal fadeout distance could be adjusted by the developers if they
noticed and cared enough. But beyond any effects constrained by the
base resolution used, you’d be hard-pressed to see visual differences between native 4K,
and the best quality presets of either DLSS and FSR.
And unfortunately, this is normally how the technology is demonstrated. For everybody’s
sake, I’m going to take a look at the limitations of BOTH technologies, if taken to the extreme,
and if compared in similar situations. To do this, I drop the resolution down as
low as I can, and I turn the upscaling techniques to their most extreme upscaling setting, because
this really makes the inner workings of each method become more apparent. You won’t game
in this way, but if it’s revealed that one method holds up better than the other at a
super low resolution, then it’s obviously managing to do more, with fewer resources,
and that sort of efficiency has use elsewhere as well.
So here’s 720p, native. I will be comparing it with 720p but with FSR’s fastest ‘Performance’
setting, in order to push AMD’s upscaling algorithm as far as it can go, in an effort
to make the upscaling artifacts most obvious. And I think you’ll agree that FSR performance
setting’s image is noticeably worse looking than native. A lot of the scene is still well
anti-aliased, but texture definition has dropped off a cliff. I’ve noticed this in other
games with FSR, too- the upscaling betrays the original art style and looks almost like
some kind of ‘art’ filter that’s been applied across the screen. The metal bars
on this gate clearly highlight FSR’s lower base resolution, as thin lines dissolve into
a blobby, jagged mess. There’s a little bit of Temporal flickering left behind the
spinning fan blades, which suggests that the image is built up from at least several previous
ones. Like I said earlier, in this game, FSR is applied to an image that has already had
temporal anti-aliasing, and these tell-tail ghostly images left behind the spinning blades
is from the TAA, not directly from FSR. And lastly, and strangest of all, the top
and left side of the screen appears stretched. I can imagine that a filter that upscales
stuff based on what’s around it would struggle to resolve details around the very edge of
a screen, so it could be that FSR’s way of getting around this, simply by stretching
the artifacts to be off the screen slightly. gets around this simply by stretching it off
the edges a bit to conceal these limitations. It doesn’t matter which setting of FSR you
use, this is always present. Stuff also seems to get ‘sucked’ off the right-hand side
of the screen, though the effect here is a lot more subtle than the abrupt line where
it begins excessively stretching stuff on the left and top. You won’t notice this
stuff unless you’re looking for it. Which I am.
Now let’s see how DLSS Ultra Performance fairs against Native. And DLSS truly shines
at low resolutions such as this one. You can see that, if anything, texture detail manages
to be some how HIGHER than with native resolution. It retains the definition on the gate nicely,
and there’s no stretching going on around the sides. But DLSS’s clarity comes at a
cost- and that’s to the image stability. It builds the image up over lots of frames
so you can see very noticeable ghosting behind the fan blades. I’m not even going to try
counting these- it looks like it’s holding onto details for a good 30 frames or so. When
pushed to the limits like this, FSR and DLSS both introduce shimmering to the scene, but
DLSS’s is more obvious and more aggressive in appearance. Everything with definition
appears to ‘crawl’ at a sub-pixel level. And lastly, we’ll compare FSR and DLSS in
this manner. FSR’s upscaling betrays the game’s art style by making details blobbier
or dithered looking, but DLSS’s is likely to give itself away in the form of trails
or motion blur behind movement, and aggressive shimmer on finer lines and details. I’m
giving the win to DLSS, though, as it reconstructs an image that far more closely resembles the
native resolution. I’ve received criticism for focusing too
heavily on still shots, so I’ll now show a run through the first level, with FSR on
the left, and DLSS on the right. Both on the fastest setting of upscaling. Obviously, they’re
not the exact same run, but it should show you how the two upscaling methods hold up
in fast-paced motion. At ultra low pixel-counts, I believe that
DLSS remains the better option for resolving motion. It displays fine details from further
away, and retains more clarity on textures. If I’m honest, any checkerboarding or pixel-crawling
present on the DLSS image is present with FSR, and if anything, is even more noticeable
with FSR when in motion. Let’s take a look at FSR on its own, played
at 25% speed. At super low resolutions, its art-filter appearance is really noticeable,
especially around the lights and on the wall behind them. It does a good job of hiding
jaggies- so it does its job well as being an anti-aliasing solution that also boosts
framerates. But the overall image quality is low.
I do think that DLSS’s image is significantly better, but around the edges of the lights
you can make out checkerboarding patterns that it has been unable to clean up. And the
reflections on shiny surfaces tend to flicker a lot more than FSR does.
Of course, it could be that at these settings, FSR is running at a lower base resolution
than DLSS is. Which isn’t helped by the obscure naming schemes and secretive nature
behind DLSS’s base resolutions.I know why AMD chose to name each of their FSR methods
a tier above Nvidia’s, but while it is dank, it does make trying to compare them even more
confusing. It’s worth noting that, although clearly
CPU limited at such a low resolution, if running at higher ones then FSR performance setting
tends to run about 7% faster than DLSS Ultra Performance mode does- so it’s not a completely
fair test here. Nothing would be, cos they all run at different speeds. But at least,
from doing this low resolution comparison, you now understand what the artifacts of both
approaches look like. So let’s move onto the final BATTLE! I’;m
going to compare higher resolution examples which happen to run at similar framerates.
So here is 4K FSR Quality, VS 4K DLSS Balanced mode. Still not completely fair- FSR runs
2-3% faster, so you’ll have to decide whether you think DLSS looks better, and if so, if
it’s worth the extra 2-3% performance penalty. The weaknesses of both methods are masked
by a higher resolution, and both are, in my opinion, highly preferable to running at native
resolution, when considering the performance penalty that that would entail.
I’ll be honest- at a high resolution, with just a modest amount of upscaling, there isn’t
much in it between the two. I was really having to zoom in and nitpick to spot the differences!
I still think that DLSS is better, but it’s a LOT closer than I had expected. It’s questionable
if you’d ever even notice a difference between the two in practice.
But I wonder if comparing similar framerates is the wrong way to go about this. FSR and
DLSS are similar if comparing their higher quality presets, but DLSS holds up better
as it drops down towards performance or ultra performance preset, where it’s having to
upscale further from a lower base resolution. FSR’s image quality drops off faster, and
the result looks more artificial. So if I WAS to extend this testing, I’d set FSR
to something like quality or ultra quality, then would see how low I could drop the DLSS
setting before its image became noticeably worse than that. I suspect that if I tested
in this way, DLSS would end up achieving similar image quality to FSR but at a higher framerate.
And if that’s the case then it’s a shame that the Steam Deck will be limited to FSR,
when I think that would be a perfect use-case for DLSS, where it would be able to achieve
acceptable results while upscaling from a lower base resolution.
But let’s be clear here: both are great technologies. FSR acts as a powerful anti-aliasing
solution, while DLSS imitates the clarity of a higher resolution, but with more artifacts.
But we’ve got to remember that the technology driving DLSS is more mature, and more work
goes into implementing it into each and every game where it’s supported. But FSR is still
GOOD. It’s still a lot better than nothing, and as the resolution and framerates increase,
the differences become less noticeable. It still gives the impression of there being
more detail than its base resolution would suggest, AND it does a good job of anti-aliasing
stuff. There was a time when anti-aliasing came with a severe performance penalty- but
these days, thanks to FSR and DLSS, it can even come with a performance boost!
And I commend FSR for being easy to implement into games, and available for everybody to
use. These factors will lead to it becoming more widely used than DLSS is. BUT, now that
DLSS is getting integrated into major game engines like Unity and Unreal, we will probably
see a lot more games featuring DLSS in the future. And I don’t know what’s going
to happen when Unreal 5 titles start coming out, since that has its own ‘Temporal Super
Resolution’ upscaling method as well! We might end up with even more upscaling methods
to choose from as time goes on. But for now, it’s FSR VS DLSS. FSR is easier
for current games to add, but where DLSS IS featured, it is better. I find it annoying
that Nvidia doesn’t share the tech, while AMD does share theirs, so Nvidia users get
the best of both worlds while AMD’s have to make do with FSR.
Luckily, the number of games in which this matters will always be limited to the very
latest and most demanding titles. Because as games get older, they become easier to
run with current hardware, so eventually they reach a point where it’s equally feasible
just to ramp the resolution up and to get great anti-aliasing in them by super-sampling
everything the good old, brute-forced way instead.
So any strengths and weaknesses of FSR and DLSS are most important RIGHT NOW, and then
will diminish in current titles as graphics cards get faster and as prices go down hohohohoo.
But before we end, there is another reason for FSR to exist. And that’s benchmarks!
For a long time, DLSS was the only technology like it in existence, and people who benchmarked
games faced a dilemma: it wouldn’t be fair to benchmark AMD cards at native resolution
VS Nvidia cards using DLSS. But if the feature is available, and players would be using the
games WITH DLSS enabled, surely it would make more sense to run the games with DLSS enabled
in benchmarks? Reviewers ended up doing the right thing.
They’d compare native performance, and then might slip in DLSS results as a bonus just
to see how they compare. But now that FSR exists, and its modes seem similar in performance
to DLSS’s equivalents- if name a tier differently, and with marginally faster performance, which
I think MIGHT be intentional- we could begin to see benchmarkers running games with FSR
and DLSS on by default. There is no longer the fear of missing out
on DLSS for anybody without an RTX card, because FSR is a decent alternative, if still not
quite as effective when on balanced or performance settings. FSR’s shortcomings remind me a
lot of DLSS 1’s weaknesses, but to a lesser extent. But perfecting these technologies
takes time, so here’s hoping that, with the groundwork now in place, FSR can continue
to build on its promises. Because we all stand to benefit.