Why do water reflections hurt framerate so badly?

Zewks

Even on medium, im getting a 15-25 FPS drop even in areas WITH NO WATER!!

Most other games, water reflections dont have such a high framerate hit, even on very high settings. Witcher 3 for example, I can run reflections on ultra, and it has a meger 5 fps drop when im NEAR or in a large body of water.

ESO on the other hand, ive done testing with it set to OFF and set to medium, and standing in coldharbors main city I get the following results

Reflections OFF: 76 FPS
Reflection Medium: 57 FPS

"Whoa, 57 still is pretty good for this game" you might say. Yes... however, there are plenty of areas that drop the framerate even lower, so with reflections ON, im seeing framerates in the 30s. So no, thats not really that acceptable for me (personal opinion, smooth for me is 60)

What exactly is the game doing with this setting? Is it calculating water reflections for the percipitation in the sky above? Is it rendering reflections for water in the sewers under the ground? Maybe its rendering reflections for the moisture in all the eyes of the NPCs. Thats the only thing I can think of that would explain it.

Nvidia 970 GTX
i7 4770
12 ram
SSD

Nyghthowler

Too many variables in the coding to answer your question, unless it comes from one of the dev's working on the graphics engine. And they aren't talking...

paul_j

http://youtu.be/NzsHrK7nY2c

Oldmanlawlor

For water to look good it has to contain a lot, and I mean a lot, of quads. More quads means more rendering needs to be done. And the more rippled the water is, the more quads that are there. And then when they get rendered the quads are split into triangles. (Atleast that's how I was shown to make water in games in college). Game engines have to a lot of *** as quickly as possible.

Did you know it took hundreds of computers working for thousands of combined hours to render one of the toy story movies?

In saying that however, one of the engines tested for next gen final fantasy games aim to handle 13 million quads per character.

FriedEggSandwich

kaylb14_ESO wrote: »

Even on medium, im getting a 15-25 FPS drop even in areas WITH NO WATER!!

Most other games, water reflections dont have such a high framerate hit, even on very high settings. Witcher 3 for example, I can run reflections on ultra, and it has a meger 5 fps drop when im NEAR or in a large body of water.

ESO on the other hand, ive done testing with it set to OFF and set to medium, and standing in coldharbors main city I get the following results

Reflections OFF: 76 FPS
Reflection Medium: 57 FPS

"Whoa, 57 still is pretty good for this game" you might say. Yes... however, there are plenty of areas that drop the framerate even lower, so with reflections ON, im seeing framerates in the 30s. So no, thats not really that acceptable for me (personal opinion, smooth for me is 60)

What exactly is the game doing with this setting? Is it calculating water reflections for the percipitation in the sky above? Is it rendering reflections for water in the sewers under the ground? Maybe its rendering reflections for the moisture in all the eyes of the NPCs. Thats the only thing I can think of that would explain it.

Nvidia 970 GTX
i7 4770
12 ram
SSD

Interesting. I have i7 980x 16gb ram, gtx titan, ssd and run the game at 2560x1440 on high. I get about 70-100fps usually in pve. The only time it drops is when there are lots of players on screen casting abilities. It can drop to 15fps in pvp though, even with nothing on my screen. Never noticed reflections affecting performance.

SgtSilock

I find water reflections to make a massive difference in frame rate. I play with them off and get over 100fps, I turn them on and I get 50-60 (less in some areas)

Dreyloch

Is that a typo OP? 12 ram? As in 12 gigs? I would say that's a bit low and might help if ya had more.

Red_Feather

Dreyloch wrote: »

Is that a typo OP? 12 ram? As in 12 gigs? I would say that's a bit low and might help if ya had more.

Maybe 3 years ago they only went up to 12 ram. Since then we can download way more.

SgtSilock

Dreyloch wrote: »

Is that a typo OP? 12 ram? As in 12 gigs? I would say that's a bit low and might help if ya had more.

A very misinformed response my friend.

Playing at 4K the game uses less than 7GB of ram. Ram also doesn’t help with frame rates, that’s your CPU and GPU, how ever more ram does help to reduce the load on your system and prevent any stuttering as the software isn’t gasping for breath.

MLGProPlayer

They don't. The biggest impact on FPS is view distance. You can double your minimum FPS by dropping view distance from 100% to 20%. The game will look like it came out in 1999, but it'll run smoothly.

SgtSilock

MLGProPlayer wrote: »

They don't. The biggest impact on FPS is view distance. You can double your minimum FPS by dropping view distance from 100% to 20%. The game will look like it came out in 1999, but it'll run smoothly.

They do impact FPS, this is a fact. Low doesn’t seem to have any impact but medium to high will reduce your FPS dramatically, regardless of view distance.

personman_145

A dev posted awhile back in PTS, that if you are CPU limited (and most are) you turn water reflections to low. Then it is done on the GPU rather than the CPU. I guess it controls more than just water reflections.

SgtSilock

personman_145 wrote: »

A dev posted awhile back in PTS, that if you are CPU limited (and most are) you turn water reflections to low. Then it is done on the GPU rather than the CPU. I guess it controls more than just water reflections.

That's good advice. Begs the question why they don't make medium and high run on the GPU instead of just low.

personman_145

I had the impression that to do the medium and high quality they needed to bring some cpu in to it, maybe they did some more advanced stuff than you can through purely gpu means. That's speculation on my part. I think I posted the dev's comments to general discussion. you can probably search my name and "multicore."

personman_145

I found the important bit, (this was during PTS for Summerset):

ZOS_AlexTardif
✭✭✭✭
PTS 1 doesn't have all of the performance improvements, there are a number of additional changes that are rolling out in upcoming PTS iterations. Quad-core machines (without hyperthreading) in particular should see a bump in the next PTS update. We're also tracking down and smoothing out hitching issues, specifically ones people encounter when running through cities and the FPS tanks abruptly for a few frames.

To give more technical details for those who are interested, you should not expect even distribution across your CPU cores after this update, just more distribution to the non-main-thread cores than you had before, especially at times when there are a lot of things loading in. Your main core thread will still be topping off, trying to go as fast as it can through each frame. For almost all of you, the bottleneck of your framerate is your CPU, not your GPU, so if you're not seeing high utilization of your GPU, it's most likely because the CPU-side of the game isn't keeping up.

Given that ESO originally had to support very old CPUs, it's no secret that it was written from the ground-up as an effectively single-threaded application. As time went on and the min-spec was updated, and with the launch of Tamriel Unlimited/XB1/PS4, it necessitated the ability to use multiple cores in order for the game to run well (as it should). The work started then and continues through the present.

It's been an ongoing process to shift work over to other cores (and to the GPU) where we can in order to make the game perform better, and the work involved in doing so is fairly complex. It's not something we can point to and say "make all cores do the same amount of work" (though that is the goal!), it's typically "this certain part of the update takes a long time, let's find a way to shift that work over to other cores." Doing that is almost always a bit of a challenge because we have to make sure the cores that do that work don't conflict with things other cores are doing, which can cause corruption, crashes, hangs, etc. We also have to ensure that the changes are positive across all the platforms as well, from the wide range of supported CPUs on Windows + Mac, to XB1 and PS4, so these changes have to come out incrementally to ensure we make the experience better across the board.

We have a lot more work to do here, and we will continue to make improvements. There's always something that can be made better.

PS: Pro tip, if you have a good GPU and have all your settings maxed but want higher performance, change your Reflection Quality to Low instead of Medium or High. "Low" reflections are actually using screen-space reflections, rather than heavy-duty planar reflections. Planar reflections are more accurate, but they're far harder on the CPU, whereas screen space reflections are almost entirely a GPU operation and should lighten the load on your CPU quite a bit.

russelmmendoza

I7 7700
Gtx 970 4gb
16gb ram
Win7 64 bit.
60fps anywhere.
300 ping anywhere.
Lagspike here and there.

Ertosi

I haven't noticed any framerate issues with water personally, but have noticed lots of other silly bugs around water.

My favorite water effects bug is how lots of various particle effects are visible even through terrain as long as you're looking at it while standing in shallow water. The most obvious and easy to reproduce example of this is over in Mirkmire where you can see the voriplasms and their minions even when they are hiding underground as long as you are looking at them while standing in water. Somehow when calculating for reflections on water, blocking terrain isn't taken into account when calculating light rays from particle effects.

A few examples:

Looking down a waterfall at some voriplasms with clear line of sight:


Same voriplasms with line of sight completely blocked by terrain:


Skeletal voriplasm minions "hidden" underground with their blobby parts fully visible through the terrain:


Note I've reported this over in the bugs section of the forums as well as in-game through the /bug feature, but ZOS hasn't taken notice. It's a shame because the bug completely takes out the fun of voriplasm encounters by broadcasting their presence.

validifyedneb18_ESO

SgtSilock wrote: »

Dreyloch wrote: »

Is that a typo OP? 12 ram? As in 12 gigs? I would say that's a bit low and might help if ya had more.

A very misinformed response my friend.

Playing at 4K the game uses less than 7GB of ram. Ram also doesn’t help with frame rates, that’s your CPU and GPU, how ever more ram does help to reduce the load on your system and prevent any stuttering as the software isn’t gasping for breath.

How would resolution effect the amount of ram needed exactly?
VRAM? yes. RAM, no.

This issue really depends on your graphics card and how exactly ZOS are doing reflections. Most likely by rasterizing the scene then mapping those as textures in the fragment shaders or something. Ive never done water reflections myself outside of raytracing (which is definitely not used in ESO) but to my knowledge this is the standard way.

Internally your GPU is doing a lot of dynamic bilinear interpolation, maybe some trickery with geometry shader data to make the waters shape match the reflection, probably a bit of warping. The games graphics industry is a fast moving world, and new GPUs are always designed to be better at whatever is needed at the time. An older GPU may not be able to do some graphics trickery as well as other cards simply because the architecture was later changed to better accommodate that shader pipeline better. Take all those new algorithms nvidea come out with for AO, CSMs, VL, and the most recent realtime raytracing tech. This is all tied to the card you're using, in part because Nvidea are ***, but also because those cards where designed specifically to better cope with that technology in the pipeline.

Oh, its also possible your VRAM is simply being paged by the additional data stored for the rendering of high detail reflections, you could lower the quality or otherwise monitor your VRAM usage to see if this is the case. If you have some cards like the GTX970 that I use, you should also know that the last .5 out of 4GB of VRAM is a slower format RAM which will cause processing on your GPU to take noticably longer (but nowhere near as slow as would be caused if paging is forcing graphics data into your RAM to cope with overhead).

SgtSilock

Dropping my reflections to low really helped and the water looks 10x better than no reflections at all.