Incredible frame rate drop with VR on an i7 8700K and RTX 2080Ti Ultra

Hello everyone. I'm new here and super excited to begin my journey with DCS world.

I recently built a rig to have a great experience with DCS using the Rift. Frame rate is ~45 on `low` settings, which is very odd to me.

Computer specs:

AORUS Z390 ULTRA

Intel i7 8700K (liquid cooled)

32GB RAM

EVGA RTX 2080ti Ultra

Triple Samsung 970 EVO 500GB - NVMe PCIe M.2 2280 SSDs (MZ-V7E500BW)

Windows 10 running on on NVME0

DCS World on NVME1

Here's a video demonstrating the performance issues. Would love to see what I'm doing wrong here.

Thanks so much!

(Youtube tag doesn't seem to be working)

On the ramp there, its full of F/A-18's, with flat shadows enabled. The Hornet is a frame hog since its release. One or more in view, especially with shadows on, will really hit fps. Not sure why this is. Maybe the model is still split in atoms, and each object casts shadows. But we can just hope that this improves as the Hornet goes trough Early Access.

That said though, your fps are still too low for your hardware. I have slight better fps than you, in the air (my specs are in my signature). So something is holding it back. No clue what though.

Regarding your youtube tag, just include the cp5sO1VDATY part.

+1 with Knock-Knock.

Static Hornets Lot20 cut in half both Gpu usage and fps when rendered to your field of view on the ramp. It's a "bug" we all have and there are 1 or 2 other things in DCS that can creates this momentary behaviour.

That said there is still something strange to me when you fly away from these statics models : you have 45fps but you don't seems to have ASW on because sometimes fps increase a bit between 45 and 90 fps (like 55 - 70 fps) BUT your GPU is low used (40% when you have 45fps).

In fact your GPU never comes above 50% load. In same time your last logical core is always high, sometimes 100%.

If I was you I would try to turn off hyperthreading (you'll have 6 physical cores only, with load spreaded accross the 6 cores much more equally, and no logical core to taxe any transistor from physical cores. I always have HT off with DCS), and then certainly overclock all cores above 4.5 Ghz (4.8 for me daily to keep vcore safe 1.24v on my 4 cores - 5Ghz no temp issue but I don't want daily OC with near 1.35v vcore).

Bitmaster made some tests and cpu OC is very important to feed correctly big GPUs with actual DCS' engine. (depending on ingame settings BTW, because others showned that 4.5Ghz is enough with certain settings)

Finally I'd say find good settings to have 45fps stable with ASW : aiming to stick with 45 fps will allow you to have good VR visuals, high pixel Density (1.5-1.7) + antialiasing (2X) and good level for other settings (visib range I use medium - maybe go high, and high also for most other settings). Of course no Vsync with VR but you surely knows.

Also in my exp. your GPU needs volts to work full stock potential, guessing it's not a watercooled GPU (WC gpu's temps are so low that stock "hypersafe" voltages are enough).

My air cooled gpu don't deliver stock potential until I set "free" software voltage with MSI afterburner (temps are low, around 60° max at full load, but it's too high for stock voltage to keep factory Oc frequency - WC gpus are way lower in temps).

Long post for maybe no magic … because gpu cpu ram is a thing but DCS engine is evolving and we can see limitations sometimes that are not possible to identify watching usages and overclockings … but improvements are to come no doubt.

Thanks for the replies @Knock-knock and @tougenglisse!

I agree that something is holding the system back. GPU Usage is ~40% which tells me that it's not the bottleneck from processing perspective. One CPU core spikes, and without looking, I have a feeling that's DCS itself.

I'll try it with HT turned off and see what that does. I turned off ASW because it was causing me to get dizzy.

In "low" settings, it seems that frame rate dropping like this could be due to an un-optimized rendering engine.

I'm downloading the latest version of X-Plane to see how it performs in this system as well.

Well, having a MUCH lower end system than you and hearing about other guys with high end systems like yours, I can say I'm getting 45FPS on mine too mostly with dips into the 30's. With PD1.2, MSAA x2, a few things set to High (textures) and shadows off. (Running the VR shader mod now, prior to that I couldn't run the MSAAx2). My 980m notebook card should be about 4x slower than your 2080ti.

My approach to optimizing things has been to start low and turning things up until the frames started to suck. In terms of DCS some planes are better than others in terms of frames/VR. I've found the RAZBAM harrier and M2k to be the among the best for VR in that regard. Most of the older Belsimtek/ED modules do OK too and the hornet is mostly ok on my system.. The Mig21 is bad though.

With your rig and low settings, I feel like you should be pulling 90frames all the time unless your PD is stupid high somewhere else, which it might be based on your screen gfx (hard to tell)?

How are you loading the game and is there any occulus or steamVR setting that could be increasing your super sampling stupid high (like PD2.0 or 200% etc)? I've heard that steamVR "sets" your super sampling for you based on what it thinks it should be and for the 2080ti thats 200% supersampling which is "demanding"

Your CPU is pegged in turbo-mode. Ironically I'll bet you could probably crank textures, anisotropic filtering, MSAA and PD up to a point, and not affect your framerate one iota. Up where the jets play I bet you do fine. Fly around NTTR at 20,000 feet at sunset, let us know.

Your cat doesn't like your machine very much. Mine doesn't either.

ETA

I'm assuming your GPU doesn't overheat and throttle down like mine does. You can hear my fan from across the street

Okay just very basic testing and if I am pointing anywhere towards or over Las Vegas 45FPS if I leave Las Vegas it goes up to 90FPS and that's not all low settings. :cry:

Nothing silly like PCIe lanes power/performance settings??

BTW I now have 30 mins on F/A 18. :thumbup: :D

Okay just very basic testing and if I am pointing anywhere towards or over Las Vegas 45FPS if I leave Las Vegas it goes up to 90FPS and that's not all low settings. :cry:

 

Nothing silly like PCIe lanes power/performance settings??

Interesting question. Ran into that building multi-GPU rigs on cheap motherboards, you start running into conflicts with USB channels among other things. Yall are running MB's that are the opposite of cheap, and it's always the fourth or fifth GPU that gets ya, but it's a good question.

I get the feeling the system is choking down a lot of data right at the "event horizon" where buildings become visible. Suspect there are a lot of potential bottlenecks. Since we are all seeing the same thing pretty much, I gotta suspect the CPU. Keep in mind we are all using one core, no matter how many $ we spent on our systems. You can make the GPU the bottleneck by flogging it to death with supersampling. Back off on that, or get a monster GPU, and the bottleneck shows up somewhere else.

[bTW I now have 30 mins on F/A 18. :thumbup: :D

Oh it's just beginning. As yet unsure how many hours I spent last practicing case 3 landings. It was peaceful though. RWR not going off constantly, no bandits for a million miles. Just the moon on the water and a highway in the sky.

Vegas schmegas.

 

Oh it's just beginning. As yet unsure how many hours I spent last practicing case 3 landings. It was peaceful though. RWR not going off constantly, no bandits for a million miles. Just the moon on the water and a highway in the sky.

 

Vegas schmegas.

It's already began. :D :thumbup:

Just the moon on the water and a highway in the sky.

We have a de Saint Exupery !

There are numerous training missions that show the framehit being caused with certain static models in view. There are a few threads talking about that issue. Aside from that the TL;DR Version is at the bottom.

What is your pixel density in the occulus tool tray? And what are your pixel density settings in the game?

Is your GPU set to "Prefer Maximum Performance" in the nvcontrol panel? And have you set up any custom fan curves for your GPU? They run better when cool. I set mine to run at 100% rpm by 45C using Evga Precision X1. EVGA also has bios updates for the RTX 2080Ti XC Ultra that can be found in the EVGA forums, not sure if it applies to the XC2 or which of the two you have. Really only a concern if you are overclocking the GPU afaik.

That being said - getting 90FPS in VR in DCS World over land is a task for hardware of the future at the moment in my opinion.. unless you want to render at a resolution like maybe half that of the rift.

With my WMR headset I just let motion reprojection do it's thing and configure my machine to run at no less than 45fps. But don't use missions with static aircraft to tune performance for the time being. That being said at with the odyssey I can get to about 2.0 pixel density and stay above 45fps with my 2080Ti.

Letting ASW do it's job should keep things smooth, although it will artifact a bit. DCS renders things much further out than just about any other game you will play. There's another sim out there I won't name that only renders objects like aircraft and vehicles and buildings within like a 12.5KM radius with your aircraft being the center of the cylinder and I just barely am able to run @80-90fps above 1000 meters in that title with 180% SS. You can see buildings and targets 40NM or further out in DCS with view distance set to medium.

*Edit* - Just looking at your Task manager your CPU is only running at 4.2ghz? Find a guide on how to OC that chip specific to your mobo. Put that liquid cooler to work. should be able to OC all cores to 4.7 at least with very little effort. I'm good @ 4.9ghz on all cores at 1.275 vcore without delidding, stress testing at 75C average under full load using a corsair h100.

DCS World is a DX11 title and single threaded performance is a big deal. You'd probably see a pretty nice increase in performance by increasing your cpu clock speeds. You are very likely cpu limited, and it seems like your CPU is using the AVX offset rather than turboing 2 cores to 4.7. Chip should easily do at least 4.7ghz on all cores with a little know how, with the AVX offset completely disabled even. K series comes unlocked for just that purpose.

Just for reference - 2080Ti's paired with a 2560x1440 monitor in DX11 titles are showing cpu limitations even @ 5ghz. At that point you're talking about delidding the cpu. I'm not recommending this, it's just a process that is probably necessary for 5ghz or higher clock speeds. But I'm willing to bet you can hit the 4.7-4.9ghz territory with little concern or effort, and there are likely guides you can find by googling your motherboard model + overclock that will help you with every setting. From there it's simply finding the minimum vcore for stability vs the highest clock frequency you can run without crashing or hardlocking (even briefly) within a certain temperature range while stress testing with your particular piece of the silicon lottery. (I'm talking specifically about the OP's 8700K)

It's do at your own risk, but if you only adjust vcore in like .005 increments (Start from 1.3 and if stable work down 1.295) you're unlikely to do any real harm that can't be fixed by clearing cmos and reconfiguring your bios.

TL;DR version

I'm using an HMD with 1440x1600 resolution per eye with Pixel Density @ 2.0, @4.9ghz, and still can see individual CPU cores hit 99% in DCS World if not using motion reprojection, although I haven't seen my gpu usage drop below 97% in the same scenario. I suspect a gnarly CPU limitation, and your system seems to be using the AVX offset, putting all cores at 4.3ghz. Your 8700K paired with a 240mm liquid cooler can probably handle 4.7-4.9ghz on all cores with the avx offset disabled and less than 1.3vcore, and that could offer a nice performance increase. That 2080Ti is hungry, and DCS World is a DX11 title that benefits from single threaded performance. I'd get used to running at 45fps with ASW on, and a high pixel density for some time to come. The good news is, you'll be able to get away with a relatively high pixel density and msaa x2.

More good news - Eagle Dynamics is working on implementing the Vulkan API into DCS World, this should make use of more cores/threads, and offer higher framerates. This one might take a couple years or more though, we have no idea yet. I'm sure there's quite a bit of learning for the team involved with that.

Actually 90FPS is doable with Rift at least, mostly, and yes I think it has something to do with rendering objects way to far out or simply not in view e.g. blocked out by mountains etc.

Actually 90FPS is doable with Rift at least, mostly, and yes I think it has something to do with rendering objects way to far out or simply not in view e.g. blocked out by mountains etc.

At what pixel density setting though? I like being able to read gauges. hehe.

Mostly single threaded game. Your system is CPU limited in DCS, it looks like it can't feed the GPU fast enough. I'd overclock the CPU and see if it helps.

Bump pixel density in VR settings to 1.5-2.0 and see what happens to GPU usage.

Hornet is frame rate hog atm, especially when there is lots of them scattered on the ground. I'd try different plane, Mirage/Viggen/F15, TF51

Stable 90fps is not possible in current DCS/hardware. I'd get used to ASW - it's been actually designed to make people less dizzy, how long you've been using VR?

p.s. running mirror may add very small performance penalty.

The harrier and m2k are among the best frame rate wise for me in VR. Also, I'd check the VR shader mod, though with your beast of system you shouldn't need it.

At what pixel density setting though? I like being able to read gauges. hehe.

Settings Here and PD=1.2

With PD 1.3 PG and Normandy wont do 90FPS at least not with my testing.

It's a slight compromise but not so bad as I thought it would be, don't get me wrong we need much improved VR support and since 2.5.4 my graphics have been very odd. I've been mainly tinkering with settings just to see what can be done.

DCS is very much CPU bound ATM, I can use the FPS indicator kinda like a compass even on the other side of a mountain range when I point the heli at Las vegas 45FPS point any where else 90FPS I visually can't see las Vegas it's behind virtual rock. In the other maps, PG for example this effect is more pronounced and sometimes there doesn't seem to be an obvious reason for the FPS drop but might explain "apparently random" FPS drops.

Anyway I see we have another update I best check whats broken and whats fixed on this one and how many times it's gona crash. :cry: