On The Current State Of Raytracing

I imagine most people at all familiar with rendering and graphics are aware of Nvidia's recent 'RTX' technologies and Microsoft's DXR. Nvidia of course providing hardware acceleration in the form of 'RT cores' and Microsoft making the DirectX standards to use them.

We've seen pretty demo's like the Star Wars cinematic elevator video first rendered on DGX super computers then revealed to run -albeit at a far far lower level of fidelity- on consumer graphics cards in realtime.We've seen a couple games like Battlefield V, Shadow of the Tomb Raider, and Metro Exodus support raytraced reflections, shadows, and global illumination respectively.

Nvidia even recently released a mostly pathtraced version of Quake II based on a Q2VKPT open source fully pathtraced implementation.

We've also seen mention of impressive unaccelerated raytracing in cryengine using a RX Vega 56 as well as mention of raytracing on the PS5 and acceleration on Xbox Scarlet.

All these demos are quite impressive and we've even seen both Unity and Unreal engine add support for DXR in publicly available demos and betas so developers can begin to push these technologies in their applications.
It almost seems like rendering technology is suddenly accelerating at light speed. That is until you begin to look at the current situation more holistically.

The current implementations offer many substantial drawbacks that cumulatively and often individually destroy the viability of the technology.


First, performance is a huge issue. The reflection only implementation in Battlefield V absolutely demolished framerates from between 58 to 64% on the RTX 2080 and 2080 TI. The $1250 2080 TI pushing a measly "high 60s" framerate at 1080p. DXR is also limited to DX12 which particularly in the frostbite engine that BFV runs on causes serious stuttering and frametime issues. A later patch ended up improving performance after many months but that 2080 TI still doesn't manage 90FPS on high at 1080p. We're still left with a ~40% performance penalty for just those raytraced reflections.

Remedy Games themselves remarked on the enormous penalties of RTX implementations in their custom Northlight Engine. They say regarding the frametime penalties, "This is a total of 9.2 ms per frame and thus an almost one-third higher computational overhead if we take 30 frames per second as the basis". Notably, this is still at 1080p with the aforementioned $1250 2080 TI. While gamers are used to 144Hz refresh rates with frametimes well below 7ms it's hard to stomach raytraced effects that would more than double frametimes for often unsubstantial graphical improvements. Current rasterized fakery has gotten so sophisticated and convincing that raytracing just isn't as substantial as it otherwise would be.

Current RTX implementations are basically suggesting that instead of pushing 4k144 or 1440p240 like many gamers are trying to do or even stay consistent and push 4k60 or 1440p144 or even regress somewhat to 1440p60 or 1080p120 that we regress all the way to 1080p60 in the best implementations with the best consumer card currently available priced more than $500 higher than the last gen 1080 TI at launch.

We're going to need to see more than a radical improvement in performance for this to be viable in current generations games. We're left hoping that Nvidia's launch of RTX was truly so incompetent that such gains were left on the table more than 8 months after launch. Though seeing that even Windows didn't support DXR or RTX features on launch and it took months for the first game to support any RTX to come out it's not such a stretch.


Second, compatibility is horrible. Only three published games support RTX raytracing as of June 2019. Arguably Quake II could be considered if you want to include a mod. Those raytracing tools in Unity and Unreal I mentioned earlier are still in very early beta these 8 months after RTX launch with little sign of rapid improvement. Bugs are ubiquitous, backwards comparability with 1000 series GTX cards, while possible, leaves performance an order of magnitude worse than middling RTX performance. Implementation into existing projects is all but impossible at this point without limiting yourself to specific raytracing specific alpha builds of the game engine editors.

Notably, while VR is quickly becoming extremely popular with PSVR and PCVR reaching over 4 million users each and Steam getting 1 million monthly active VR users as well as Facebook launching the $400 Oculus Quest, there is absolutely no RTX support whatsoever. There isn't so much as a hint that maybe, just maybe, one of the dozen multi-billion dollar companies currently pouring hundreds of millions into VR are even considering exploring raytracing support in VR.
Obviously performance is a bigger consideration for VR as well if compatibility was even considered.

Related to compatibility, most raytracing tools are locked down from developers. While some major studios are working closely with Nvidia and Microsoft to integrate DXR and RTX into their custom game engines and indie developers will presumably get proper tools in Unreal and Unity eventually, right now there are very few options to actually modify an implementation of raytracing yourself. Current DirectX raytracing implementations often and seemly universally forgo hardware acceleration so those RT cores become moot. 


Third, as alluded to before, rasterized fakery has gotten so good that it's really difficult to justify the aforementioned issues. While realtime denoising has gotten pretty good, there are still many noticeable artifacts in all available demos. The current level of fidelity reached with these implementations falls very far short of even these established baselines in rasterized games. While raytracing will almost invariably provide more realistic lighting and effects, that doesn't mean that they will look better than rasterized games. Remedy themselves faked incredibly good looking lighting in their last game Quantum Break. Even photorealism is nearly achieved using these primitive techniques that manage to both perform so much better and offer so much better compatibility than any raytracing implementation currently available.



All of this leaves such a sour taste in my mouth regarding realtime raytracing that it's hard to imagine that it will have any real place in gaming outside of the very narrow niche of enthusiast gamers with far too much money to spend that also don't care about pushing super high resolutions, VR, or high framerates. I really do hope I'm wrong.

On Core i5 bottlenecking

Sure, a good Core i5 is going to be more than you'll ever need for regular gaming.

That is until you actually decide to play one of a huge variety of surprisingly CPU intensive games.


For reference, I have a relatively high end Core i5-4690 paired with a GTX 970 with a 144 Hz monitor and according to post after post online I should never run into any CPU bottlenecks because single core performance doesn't get much better and games don't really use that many threads. Right?

Anandtech's benchmarks say that my processor is the best CPU based on the Haswell architecture or earlier to run a game like Battlefield 4 with a similar GPU to mine.

Tom's hardware remarks:

"Top-end CPUs offer rapidly diminishing returns when it comes to gaming performance. As such, we have a hard time recommending anything more expensive than the Core i5-6600K"

TechSpot benchmarks show no significant difference in Battlefield 4 performance with a 290X between a core i3-3220 and a core i7-4960X.

Logical Increments still recommends a similar caliber CPU to mine (Core i5-6600) for GPUs a decent bit more powerful than mine such as a R9 Fury.

And /r/buildapc notes in their wiki:

"[i5s] are currently the most popular CPU for high end gaming as the performance benefit of an i7 is negligible and not worth the price increase for many people."


After reading these comments from a large variety of very reputable sources in the PC building community one might be inclined to purchase a $200-$250 Core i5 rather than dishing out another $100 for a "negligible" performance improvement in "high end gaming".

The problem is that in everything I've tested in extremely popular games such as Battlefield 4, Rainbow Six Siege, Grand Theft Auto V, and Civilization V prove that my processor is woefully inadequate for the task.


Some anecdotes from my experience include Battlefield 4 running at roughly the same frame-rate (within 5%) running at the minimum preset verses the high preset. Looking at the Rivatuner overlay I see that on minimum settings my GPU is running at <60% usage the entire time. This is the clear marker of a CPU bottleneck.

Playing Rainbow Six Siege results in similar trends. I am unable to push the frame-rate of the game above about 125 Fps at 1080p regardless of the settings I choose. Another notable symptom is the fact that all four cores of my Core i5-4690 are pinned at 100% CPU usage the entire time I'm playing the game.

Civilization V takes its sweet time to process the AI once you get a few turns into a game.

Also, Grand Theft Auto V which was released initially in 2011 refuses to run over 100 Fps on my computer no matter what I've tried.

God forbid I try to download something in Steam when I play Battlefield 4 because instead of 100-150 Fps, I'm suddenly running a stutter filled mess at less than 45 Fps.


I've attached some screenshots in Rainbow Six Siege below with a RivaTuner overlay.

I also have reports from others like /u/UN1203who remarks that:

"Hey so the results are in and I have to say I was wrong, and you might be on to something. I was seeing FPS scaling all the way up to my max overclock of 4.8ghz on a 6600k. Here are the pics for you.
2.5ghz
3.5ghz
4.8ghz

I could not get back to the same spot for screenshot 3 because the map had changed, but I picked the spot on the map where my sustained fps was the lowest.
Ultimately I don't really remember what it was like to play BF4 at anything under 4.4-4.5ghz and I didn't figure it would scale at all after the 3.9ghz your chip puts out but it certainly does. So it looks like it's upgrade time for you my friend. Get more cores or get to overclocking... If cost is not a major concern for you as you say, wait for the broadwell-e to drop, put that bitch under water, and let her stretch her legs at 4.5ghz+, that will be an absolute monster. And with BF5 coming out soon you will want all the firepower you can get."

I'm stuck with this huge disparity between the information I'm given and the results I'm experiencing and finding the solution for this beyond my knowledge. I see massive stagnation in the high end enthusiast processor market with Broadwell-E failing to improve the performance per dollar rate over Haswell-E and even failing to improve maximum performance when overclocking according to a decent number of reports.

I guess I'll try upgrading to a core i7-5820k and hope that does the trick and I'll let you guys now how that turns out.

Thanks for reading.

Edit:
Some people are asking for a full spec. list so here it is:

Intel Core i5-4690

GTX 970
Windows 10

16GB 1866MHz DDR3

Edit 2:

I've read comments talking about how clearly I'm an idiot and there must be some other program in the background ruining my performance, Windows 10 is the spawn of Satan and idles the processor, and that I should just be happy getting around 100 Fps and just give up on expecting a locked 144 Fps on new games. I love how people love to condescend and spout "user error" on anything that makes them consider some other person's reality.

My response is simple, I'm not content with "good enough". I want and expect great performance with great hardware and I value smooth and responsive game-play above all else.


I understand that adaptive-sync will help but 100 Fps is 100 Fps. I want 144 Hz or higher.

I'd also like to clarify that BF4 stuttering while downloading from Steam is entirely due to CPU usage. I'm downloading to a different drive, my internet is fast enough, and I have more than enough RAM.