Portal With RTX Explored: Legendary Valve Classic Gets A Gorgeous Ray Traced Makeover

You probably aren’t aware of the enormous influence the game had if you weren’t a PC gamer in October 2007 when the original Portal was out.

It made its debut as a component of The Orange Box bundle, which also included Team Fortress 2 and Half-Life 2 in their entirety. It was regarded as the set’s underdog.

A title that today ranks among the greatest of the great in the pantheon of PC games was made up of striking visual design, hilarious memes, insightful narrative, mind-bending puzzles, and a stunning twist at the end that cleverly confounded players’ expectations.

The game Portal is both young enough to not appear dated and old enough to be recognized as a replica of actual places.

This, combined with the fact that it has great acclaim, makes it a prime contender to be the following game to benefit from NVIDIA RTX ray tracing.

Yes, we now have Portal with RTX after Quake II RTX and Minecraft RTX.

Similar to those games, it completely reimagines the original title and uses a path-traced renderer rather than a hybrid engine, which is what the majority of commercial games with ray-traced effects do.

In contrast to other games, NVIDIA’s RTX Remix tool is being tested with Portal with RTX.

These ray-traced remakes are beloved by graphics nerds like your author, but as NVIDIA acknowledges, they require a lot of work.

These ray-traced remakes are beloved by graphics nerds like your author, but as NVIDIA acknowledges, they require a lot of work.

By making RTX improvements simpler to produce, NVIDIA aims to outsource part of that labor to the video game modding community, maybe following a cue from Elder Scrolls creator Bethesda Softworks.

That is the aim of RTX Remix, a product based on Omniverse software.

Thankfully, there’s no need to tinker with external utilities or install additional software, at least in the case of Portal with RTX.

It is available as DLC for Portal on Steam and takes up an additional 20GB of disk space in addition to the 5GB used by the original game.

Given that Portal with RTX includes more than just an improved engine, the vast majority of that additional size will consist of higher-fidelity assets.

Graphics Aren’t Everything, Except When They Are

How does it look to update the graphics on a game that is fifteen years old?

Well, great sums it well.

But initially you won’t see it.

In fact, Portal with RTX makes a terrible first impression, at least according to our early review copy.

The starting room in the original game includes intense direct illumination to display the bloom effect, which was new at the time.

The floor is a distinct type of concrete tile, and the walls are white concrete.

The room’s surfaces in the RTX version, however, are all made of a strange material with dimples resembling those on a golf ball.

It goes without saying that I was initially unimpressed, and it takes a few test chambers before you really find a situation where the ray-traced graphics can shine.

Although there are sporadic flashes of illumination and reflection, such in the elevator image above, it initially appears to be very uninteresting.

All bets are off, though, after you reach Test Chamber 06, which is the game’s seventh level.

The “High-Energy Pellet,” a slow-moving ball of energy that bounces off walls and is essential to solving many puzzles in the game, is introduced for the first time in this test chamber along with non-portal-able surfaces.

Real-Time Denoisers, RTX Direct Illumination, and ReSTIR GI are three crucial technologies in addition to the well-known Deep Learning Super-Sampling (DLSS) that are at play here.

Reservoir Spatio-Temporal Importance Resampling Global Illumination is the most alarming of the three.

ReSTIR has been briefly discussed in the past, but to our knowledge, this is the first time it has been used in a real video game.

ReSTIR, to put it simply, is a very recent algorithm that can be used to any type of lighting in a 3D renderer.

Compared to certain other methods of path tracing, it is relatively approximate, but this gives it the ability to be very effective.

This implies that scenes can use hundreds of lights or even thousands of lights with little additional performance expense.

Global illumination (GI), which is essentially the antithesis of direct illumination, is being implemented by NVIDIA here utilizing ReSTIR.

The latter does exactly what it says on the tin: it shades pixels according to how they are directly lighted by scene lights.

The remainder of the scene is therefore lighted by GI using indirect lighting, notably bounces from sources that are directly lit.

Realistic global illumination is quite computationally expensive, which makes it very challenging.

There are several “fake” GI options in use in games; in fact, it’s possible to say that the usage of faked GI is one of the distinguishing features of eighth-generation video games.

There is nothing “artificial” about path tracing because we are accurately simulating how light moves through the picture.

Without the real-time denoiser from NVIDIA, none of this would function.

We must reduce the number of rays per pixel to tens or even just a handful since offline 3D renders for movies and other applications may fire a thousand or more rays per pixel.

Unfortunately, that’s insufficient to provide us with a solid image, therefore effective denoising is essential to producing the lovely sights you’re viewing.

We have to confess that it works quite well. According to NVIDIA, the denoiser utilized in Portal with RTX is a novel type that leverages spatio-temporal data exclusively for denoising path-traced images.

Dark areas frequently exhibit a “shimmering” or “sparkling” pattern in Quake II RTX and Minecraft RTX.

Because of the incredibly small number of rays being cast, the denoiser is unable to completely stabilize the image.

With RTX, Portal offers essentially none of that.

Although it isn’t yet faultless, Joe Gamer is unlikely to ever discover it at this point.

We also have to give NVIDIA’s DLSS credit.

The majority of these screenshots were taken with DLSS set to “Performance” in 1920 x 1080 resolution.

You definitely wouldn’t have realized that the images you’re viewing were originally rendered in 960540, do you?

Although distant objects can occasionally lack clarity due to the low input resolution and give the game a very soft appearance, overall it’s not at all unpleasant to look at.

Additionally, there is absolutely no discernible ghosting, which is astonishing given the low frame rate.

Complete Path-Tracing Is Extremely Difficult

On my personal desktop, which typically includes a Ryzen 7 5800X3D and a GeForce RTX 3070 Ti, I tested the game.

I have a high-frame-rate 3840 by 2160 monitor, so it makes sense that Portal with RTX first launched in that size.

I was unable to get the game to operate at a frame rate higher than 30 FPS, even with DLSS set to “Ultra Performance” and an input resolution of 1280 x 720.

The game wouldn’t operate at a frame rate higher than 30.

However, I noticed a relatively low GPU consumption and started looking into the issue.

It turns out that Portal with RTX is in some way a “background program,” and as a result, it is impacted by the “Background Application Max Frame Rate” setting in the NVIDIA driver.

I was able to obtain more than 30 FPS after disabling it, though not significantly more.

I was only able to achieve roughly 25 FPS in the majority of scenes when using DLSS in “Performance” mode, which gave me a 1920 x 1080 input resolution.

I could increase it using DLSS Ultra Performance to a maximum of about 45 FPS.

I ultimately ran the game in a 19201080 window with DLSS set to “Auto” simply to see how it looked.

It appears that the majority of the time, the game had the “Performance” or “Balanced” presets selected.

On a brand-new launch, I was able to achieve up to 70 FPS in straightforward situations, but as you play, performance quickly deteriorates.

After about an hour of play, the game started to warn me of low VRAM, and when that happened, performance would drop precipitously. This suggests that there may be something close to a video RAM leak.

If I played about with the settings too much, it happened faster.

As a result, you should view this framerate chart with a lot of caution.

This is due to the variable performance of RTX with Portal at the moment.

A GeForce RTX 3080 Ti, an RTX 3080 10GB made according to the original formula, a GeForce RTX 2080 SUPER, and a Radeon RX 6800 XT were the GPUs we briefly played the game on.

Although the performance is still incredibly poor for this tier of GPU at this resolution, the GeForce RTX 3080 and 3080 Ti run the game substantially better than our RTX 3070 Ti and should definitely be using higher settings.

The two other GPUs weren’t really enjoyable, however.

The main difference is that the old Turing card still supports DLSS, and running in 1920 x 1080 with DLSS set to “Performance” gives you a playable experience—at least until you run out of VRAM. This is in addition to the enormous frame rate differential.

I had to use NVIDIA Image Scaling, which is similar to AMD’s Radeon Super Resolution, on the Radeon RX 6800 XT in the meantime.

The far more straightforward NIS performs substantially worse than DLSS in cleaning up the low-resolution input for higher-resolution output.

The image has obvious pixelation and has a harsh aesthetic.

There is also a TAA upscaling option if you prefer smearing to crunchy pixels, but I think it looks much worse than NIS, with lots of fuzzy artifacting and poor quality.

Maybe DLSS has spoiled me.

Although AMD’s RDNA 2 Radeon cards’ subpar ray-tracing performance is well known, we can attest that playing Portal with RTX does indeed work if you must.

Just make sure your Radeon is powerful and be ready to drastically reduce the settings.

There are other visual quality parameters than the render resolution that you can change, but after a certain amount of fiddling, Portal with RTX starts to lose some of its appeal.

Hopefully AMD’s upcoming Radeon cards are more capable of playing this game.

Conclusions And Experiential Takeaways From Portal With RTX

NVIDIA undoubtedly would have preferred if we had shown you the game’s performance on the GeForce RTX 4080.

After all, boosting Ada Lovelace’s expertise in path-tracing is the whole goal of Portal with RTX.

The GeForce RTX 4090 is able to run Portal with RTX at triple-digit framerates when DLSS 3 with Frame Generation is enabled, even at 4K resolution.

Our RTX 40 series GPUs are all currently active and working on other projects because, regrettably, the stars did not align for us.

We’re hoping to come back to this page soon and include the RTX 4090 and 4080 results.

Even though the GeForce RTX 4090 is a far cry from the RTX 3070 Ti, which we mostly utilized for testing, the fastest GPUs according to the Steam hardware survey are quicker than our old Ampere card.

In contrast to Quake II RTX, if you own a GTX GPU, you’re just plain out of luck.

You won’t have fun even if you have an RTX card that is significantly slower than an RTX 3060.

In fact, we anticipate that even an RTX 3060 will have significant difficulty.

After all of that, should you even try to run Portal with RTX if you do have the GPU power?

Absolutely.

In the end, what Portal with RTX signifies rather than the game itself is what makes it so fascinating.

The notion of seeing an explosion in “RTX” copies of vintage games is intriguing, especially if the RTX Remix tools are as simple to use.

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