Gadgetory

hey everyone I'm Steve from gamers Nexis dotnet and this is our fallout 4 volumetric lighting benchmark and explanation of volumetric lighting in fallout 4 when benchmarking fallout 4 on our lineup of GPUs we noticed that the r9 390x was outclassed by the GTX 970 at 1080p with ultra settings this has certainly happened before in some very specific games but it's rare and it caught us by surprise that given the 390 X is comparatively high raw horsepower the performance differential was still about 5% at 1080p favoring the GTX 970 which theoretically should perform a little bit lower in frame rate than the 390 X so this gap is reversed a little bit when moving to higher resolutions like 1440p we see the 390 X actually pull ahead and that reversal makes sense because the 390 X should be objectively superior at 1440p than the 970 it's just capable of handling more pixels but the advantage 970 at 1080p required more research to fully appreciate so that's what we're here to do today these findings spurred on a day's worth of research of settings and that unveiled a few settings that heavily impact FPS but we were never able to produce any particular favor toward one manufacturer or another by changing these it generally kept the same Delta just with a higher FPS output by lowering settings shadowdistance is a really good example of this we saw FPS wins of about sixteen point seven percent which translated to around 20 FPS on the 970 and the 390 X when lowering shadow distance to medium from ultra but even with these changes the 970 still outperformed a 390x at 1080p and that was worth investigating further so we eventually discovered that console commands can be used to toggle levels of volumetric lighting and godrays in the game which seemed to impact FPS fairly heavily and you can do this by using the tilde button and then do gr and on or off or you can just type gr and look at all the options you can set detail levels and debugs and things like that as well fallout uses Nvidia's volumetric lighting effects and godrays something that immediately sort of through a red flag as a benchmarking item for us so for the unfamiliar volumetric lighting is named such because it appears to sort of creep through the air and it interacts with other volumetric effects like smoke and fog and clouds and in games with volumetric particle effects this is another big visual gain to have the volumetric lighting interaction as well and fallout for volumetric lighting is primarily comprised of godrays which are basically just shafts of light that shine down from the Sun or other very bright sources of light and we decided to run benchmarks and see if the 390x can outpace the 970 at 1080 and take a lead when God rays are disabled on both devices before we get to those results though let's get back into some basic information on how God rays work and talk about the way the beams are actually displayed in the game and translated through the engine and things like that so God rays cast beams of light that also interact with reflective surface materials and shadows and generally create the apparent depth that is given in some of these objects and what you're looking at right now is a debug tool built-in to Fallout 4 and the tool shows us the presence of God rays using two different modes wireframe which creates red and green wires indicating strike points and light passing and then godrays only which turns off all of their light sources and shows only the illumination created by a god raise the ladder the god rays only mode is extremely useful in understanding exactly why God rays are volumetric in this game and shows that even when an object isn't directly in the line of a beam of light it will still receive light from illumination shed by that beam hence volumetric and actors in the vicinity actors being NPCs in this game in the vicinity of reflective materials will receive some of the light from God rays as well so because volumetric light can bounce and proliferate when inner acting with certain surfaces you'll see that standard standards by passers-by those types of people in the general area will receive light from the reflectivity and the bounce and things of that nature we talked about this in more depth in our GDC 2015 interview with Crytek who explained physically based rendering to us we talked about star citizen and things like that so do you check that interview out to go to the channel and just search for physically based rendering you'll find it or Crytek probably and with Nvidia's implementation of volumetric lighting everything is done using tessellation or the process of effectively doubling the triangles on the graphics hardware for increased apparent detail so tessellation that's what it does it ultimately doubles triangles it increases triangle count and creates more apparent detail that where the parent is very important because it's really just an appearance thing it looks like more detail but in the game the Polly's it's still the same polygon count it's not increasing the poly count and walls or faces or anything like that this apparent detail increase allows for more displacement and smoothing of surfaces something we talked about with Epic Games in an interview JH searched the channel for tessellation for that and tessellation also creates the appearance of high resolution surfaces which means you'll see more bumps and divots and generally higher fidelity and apparent depth with volumetric lighting through Nvidia's fallout for implementation which uses game works the lighting is fed through tessellation processing instead of post-processing effects which will sort of hammer the GPU clock and eat more cycles so there's a valid reason to move the tessellation especially because tessellated lighting gives the advantage of allowing light shafts and effects an illumination to still show even when the source of light is obfuscated by some object in the game or something like that tessellated lighting lends itself to cooperation with occlusion and is exactly why you can see the light poring over the edges of a surface area or a surface rather even when that surface is physically blocked for the light source so if the lights if you were looking at the Sun and you sort of walk around a building that building ends up blocking the Sun but you can still see the sun's rays being cast around the edges of the building like the roof or something that is a result of using tessellation and Vidya as it happens is really good with tessellation and they know this and they built their architecture around optimizing it for tessellation and games look at the witcher 3 with hair works that's all tessellation and am these struggles with it so again look at the witcher 3 with hair works md is not great with tessellation they're good at a lot of things they're good at different things than nvidia each company has its advantages from its architecture they've taken different approaches philosophically to their architecture but the use of tessellated lighting does mean that andy will struggle a bit in this regard and fall out at least so we tested that stuff first off note that our original bench course took place during a nighttime playthrough around 11 p.m. in game and that created the best mix of GPU workload for FPS testing this new test for volumetric lighting strictly was conducted during the games at daytime to get the most exposure to god rays here's a look at the chart showing tessellation impact on the 390 X and the 970 obviously the FPS results will be different than the previous test because it's conducted at a different time of day different weather or things like that the 390x still trails the 970 at 1080p even when both device is disabled godrays and that's probably an optimization issue or drivers or something with the game but we still see a measurable performance gain for each device by toggling God raised and the 390x has the biggest gain of the two it moves from 71 fps 280 FPS average and increases its 0.1% bottom line considerably to 44 from 36 by disabling God raised the average FPS gain calculated is about 12% and the 970 s average FPS gained is about 7% it moves from 81 to 87 fps so the gap shrinks but the 970 still retains its lead at 1440 the 390x still runs just ahead of the 970 thanks to the 390 X's advantage in the additional pixel workload processing Department the 970 kind of gets bogged down by all those extra pixels and the gap is of course shown still when you toggle godrays so if you need some extra performance that's a good way to do it what we found though ultimately is that even disabling many of the volumetric lighting effects will not inherently grant Andy a performance advantage it fixes a lot the performance advantage for AMD is a larger Delta than for NVIDIA in general because of the way the optimization works but the gap is still there it's not eliminated this is a good way of improving your performance of about 12% or so on something like a 390 X so if you do need a quick gain for performance then I would suggest playing with godrays but it does take away a lot from the games environment because the game isn't particularly impressive and the textures and modelling Department anyway so make your changes wisely shadow distance and godrays are the places I would start the gap is still present for AMD and NVIDIA even with volumetric lighting off and if you like this kind of content check out our patreon page to help us out help us make more of this or just hit the channel and watch the other stuff cuz that's the biggest way you can support us is by watching more things or reading things on the website that's all for this time I will see you all next time