Are your frame rates low in DCS 2.5.6? You’re not alone!

As Open Beta versions of DCS World go, 2.5.6 has been one of the longest stretches of inconsistent performance issues in recent history. There are frame rate drops and visual glitches all over the place in 2.5.6 and so if you’re one of those experiencing problems right now… You’re not alone.

Inconsistent frame rates and visual artefacts

DCS World has always been a bit of a performance hog but then find me a flight simulation in history that wasn’t one. Performance stutters going back through the years have been a constant problem for flight sims and also a vital part of the experience to give you that smooth feeling of actually flying an airplane.

High end PC’s and lots of performance tweaking has always been a necessity to get most sims to run well. Most of the time in recent history, I’ve been able to get DCS World 2.5 working at a very good clip with a near constant 50-60fps and only occasional glitch. That’s a good experience and one that I like to see in most of my sim titles. X-Plane 11’s struggle to reach beyond 25fps has been a major point of annoyance for me and so the recent upgrade to Vulkan for that sim and the jump that most users are seeing has me excited for the future there. Unfortunately, DCS World in 2.5.6 has been very inconsistent.

The worst experiences I’ve had recently are in the Fw190A-8 and the F/A-18C. In single player the Fw190A-8 was a huge problem with one of the performance sucks apparently being the visual effects for the propeller blade – reducing my performance to 12-15fps from my stated average of 50-60fps. Fortunately that one issue seems to be fixed and the Fw190A-8 is much better now!

Then there is the F/A-18C Hornet which is fine sometimes and a total disaster other times. It’s apparently a combination of an nVidia driver version, the SA page (for datalinked contacts) and the bypass switch on the countermeasure dispenser. Say what? Yeah, you can read more about that here.

In multiplayer, just sitting on the apron at Al Dafra air base caused me to see frame rates in the teens with most players in the chat reporting that it might get better as I flew away from the airbase.

It did… until I turned on the SA page.

Even outside the plane the SA page ate into the frame rates. Obviously something is wrong here.

Another plane recently experiencing a problem is the DCS: MiG-21bis. Awaiting some upgrades from Leatherneck/Magnitude 3, right now if you turn on your radar and it connects at all with ground clutter you’ll see a major frame rate loss. Multiple people have posted about that recently.

Then there are the sometimes random flashes of light. You may have seen these and worried that your virtual pilot was being abducted by aliens.

Get out your aviators… because that’s a very bright light!

Every plane in my four person group landing at this airbase had the same experience. A couple of them were so blinded that it caused them to crash their aircraft at a critical moment. It’s obviously not an isolated experience.

That said, it’s not all bad either. Flying aircraft like the F-5 Tiger II the other night and I hardly saw a stutter. The same was true with my recent flying of the F-86 Sabre which flew smoothly and my frame rates stayed just as smooth – even in multiplayer!

It started with 2.5.6

While 2.5.5 had been fine tuned into a really smooth experience and if you’re on the public release structure right now, you’ll still experience that relative smoothness of that release. If, however, you’re on the open beta as most who play DCS World multiplayer are, it’s a whole other world.

I suspect many of the changes came in because of the lighting changes. 2.5.6 looks better than DCS World has ever looked and that likely came with some deep changes to the rendering systems. While some of those changes have resulted in some stunningly beautiful scenes, they are also likely at least partially responsible for all of the issues.

You’re not alone

The thing that strikes me right now is that a lot of people are asking everyone else, “hey is your frame rate bad in DCS right now?” And when they ask a lot of people respond in the affirmative. It’s a wide spread problem and it’s also one that Eagle Dynamics community managers are aware of.

Replying to messages on Facebook, Reddit, and on the official forms, we’ve heard from BIGNEWY and NineLine that the team is aware of the problems and are working on fixes for them. This is part of the open beta experience that so many in DCS World are signed up for and while the problems being spotted by the community have no doubt proven useful in tracking down bugs and squashing them… it does remain a sometimes frustrating experience.

So, with some hope, I do think we’ll see a lot of these issues go away and performance to improve but it may be a patch or a few away yet. DCS World 2.5.6 still has not yet moved to the stable branch yet and that tells me that Eagle Dynamics knows that these need to be sorted out.

I do hope to be able to scream through the skies at 60fps again very soon!

28 Comments Add yours

  1. Gretsch_Man says:

    What a bummer! I got into DCS just recently (it was the Tomcat that sucked me in…). Still playing 2.5.5 Steam version, stuttering IS an issue with VR (Oculus Rift S), even after turning down many of the graphic options. Naturally, I was hoping 2.5.6 would bring some improvements here…

    Still having hopes that Vulcan may open the door to better performance. What do you think? I for once will keep my fingers crossed.


    1. clannk says:

      look over at thud’s vr4dcs blog and the youtube “dcs vr optimization” by lukas. following the tips in those 2 places made a huge improvement in VR performance

      Liked by 1 person

      1. Smoky says:

        And zero improvement for me. YMMV


  2. Fernando says:

    Thanks for the report. I can confirm all of the problems. Hope next week some fixes will arise. Or more problems with the SC? soonTM

    Liked by 1 person

    1. Gretsch_Man says:

      Thanks for the heads-up. I tried some of those and while I was able to made some improvements, it’s still far from optimum. IMHO, much more optimization in DCS is needed, at least for VR users.

      Liked by 1 person

  3. “DCS World has always been a bit of a performance hog but then find me a flight simulation in history that wasn’t one.”

    Falcon BMS runs very solid, even on my laptop! (Although that’s mainly attributable to its old age and 2D map)

    Liked by 1 person

    1. ShamrockOneFive says:

      When Falcon 4.0 came out there were advertisements for computers capable of running it. It pushed PC’s right to the edge.

      I’m not surprised that it runs smoothly now.


  4. Terry Barnes says:

    Its not a major bug, but the ground pathing for the AI HUMVEE in the TAXI missions for several of the Aircraft is now FUBAR , with the vehicle driving off into the grass, and around trees, buildings and etc… Not a problem that really has impact on playing, but a bug none the less. I was using the TAXI training to get familiar with the free Modules we are so kindly allowed to access this month . If not for that , I would never have known most likely.

    Liked by 1 person

    1. ShamrockOneFive says:

      They have been working on ground pathing in advance of a future dynamic campaign system. Obviously we’re at the baby steps level here.


  5. grammaton632 says:

    A consequence of modding an ancient codebase. Dual-core doesn’t cut it anymore. The situation for DCS VR is dire. ED dev’s stated recently that Vulkan support is in development but will take a long time. You can forget Vulkan support in 2020 and 2021 is probably unlikely as well.

    We’re having to use much more powerful hardware that’s not utilised anywhere near capacity.

    VR acceleration features built-in to every Nvidia GPU since the 900 series could bring smooth performance to DCS even on the current DX11 API as well as maximise performance when Vulkan eventually arrives. Even adding just one feature from VRworks API – Single Pass Stereo could potentially double FPS in VR and the VRworks API is transferrable to Vulkan as well.

    The non-beta DCS offers smoother performance in VR but still relying heavily on bruteforce hardware and VR driver motion smoothing tricks like ASW and Dynamic SS.

    Liked by 1 person

  6. grammaton632 says:

    “DCS World has always been a bit of a performance hog but then find me a flight simulation in history that wasn’t one.”
    I found you one… It’s called IL-2. Much smoother performance and it supports SLI. The devs have massively improved performance on IL-2 in a relatively short time.

    XP-11 now supports Vulkan with much better performance.


    1. ShamrockOneFive says:

      IL-2 runs great these days although at various points it too was a bit of a hog – though it is possibly the smoothest running sim. It seems to have been a conscious effort.

      Liked by 1 person

      1. grammaton632 says:

        Considering IL-2 got VR much more recently… They’ve optimised it well and added SLI (for what it’s worth) quickly. The first release of VR support for IL-2 was accidental. It was a member of the team (perhaps drunk) releasing it to steam before it was intended. Caused a backlash and they apologised. But they brought a functional version relatively quickly. DCS has had VR support for a long time now and the improvements in performance have ALL been attributed to VR driver performance tricks by Oculus and Valve. In other words.. the only way it’s playable at all is because of those companies.

        All that could change if Eagle added some VRworks API acceleration and of course when Vulkan comes in a few years time.

        Liked by 1 person

  7. banzaiib says:

    It’s not the lighting causing the framerate issues, it’s the refactoring of the netcode and unit synchronization. You can test this by loading progressively more units and watching your GPU utilization drop. Framerates are still fantastic on clean maps, but as unit sync bogs down the APIs, so goes your framerates. This means that 50+ player sessions with hundreds of units is impossible.

    Liked by 1 person

    1. ShamrockOneFive says:

      Very interesting. I can’t help but think the lighting updates still are part of the reason why drawing some screens like the GUI for the SA page in the Hornet or the radar contacts with the ground in the MiG-21 cause such performance loss.

      But you’re likely right there’s more going on than that and unit syncs might be the cause too.


  8. banzaiib says:

    It’s not the lighting that’s causing the framerate issues, it’s the backend API that synchronizes units. You can test this by loading a clean map and enjoying the 100+ FPS, then progressively add more units and watch as your GPU utilization slowly drops as does your framerate. This tells me the GPU is waiting for some kind of sync to happen and thus the opposite of what should happen, happens. When the most units are in a map, the GPU is utilized least.


    1. grammaton632 says:

      The reason for this is everything is trying to run on a single-thread. So as more units are loaded, the struggle gets worse, and as you observed, the GPU is waiting longer and longer. You’d have to run DCS around 10ghz on a core to compensate for the lack of multi-threading.

      Liked by 1 person

  9. a b says:

    Revisiting DCS VR now that I have a new headset and was really surprised at how low my frames were. For those that have been following the VR issues over the last few months would you say that the issues still exist?

    Liked by 1 person

    1. ShamrockOneFive says:

      They definitely still exist. The last open beta shored up some performance issues but not all of them. Even non-VR users are struggling right now.

      I wrote about the issues a couple of times recently and I have to say that my DCS World flying has been severely curtailed because of these issues. I hope that their new release cadence with slower release cycles will help.

      Liked by 1 person

  10. grammaton632 says:

    Oh yes… they actually existed before the lighting update and of course things were even worse then. Supercarrier adds more burden even though it’s amazing. I see the horror on a daily basis.. I’m a member or DCS World VR aviators on facebook. The lengths people go to to try and reach a baseline performance. Some people believe they have good performance but when you drill into their statements.. it’s largely Oculus ASW helping them.

    I’d like to see a real big push and outcry from people on getting ED to improve performance with the first VR performance boost. Up till now they’ve relied exclusively on 3rd party tricks like ASW or steamVR motion-smoothing. People are buying 2080Ti’s to chase baseline performance when even a GTX 1070 isn’t utilised anywhere near capacity in VR on DCS. VRworks VR hardware acceleration could really boost DCS performance. It would also be compatible with Vulkan down the line.

    Liked by 1 person

  11. Shane says:

    I wish DCS would improve the VR game play it is so frustrating. VR is the wave of the future and 2D is an old technology not worth pursuing anymore. They have a chance to catapult themselves into the future as a simulator lead and they are just sitting around creating more issues.


    1. ShamrockOneFive says:

      I’ve heard VR performance remains a serious issue. It sounds like their efforts under the current engine to get more performance haven’t really worked out.

      The still far off Vulkan API and engine overhaul will probably be required to really get it where it needs to be for VR.

      Worth mentioning that VR is definitely going to be a growing space for flight sims but there are still a majority on 2D screens. We’ll be flying with both as part of the constellation of setups for a long time yet.


  12. MeatServo says:

    Try turning Low Latency Mode to Ultra in the Nvidia control panel. This solved my frame rate issues, and low GPU usage.


    1. ShamrockOneFive says:

      Thanks MeatServo. That may help in some cases, though when this article was written, the state of DCS World was not good and successive beta patches had degraded performance for many players.


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