What is RdrThread and why is it nuclearly destroying performance on my system?

Bug Reporting Hub Install, Performance & Graphics
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ISSUE DESCRIPTION

Description of the issue:
I don’t know really how to describe it, but it seems the sim overloads my CPU and my GPU via RdrThread and my system doesn’t know how to react, causing the sim runs to like very low framerate for a fairly recent system, even for MSFS 2024 and I have rather mid-high options.* *At first, I thought it was a scenery issue, especially in inibuilds Heathrow. Then, it seemed to be really random on any scenery and any plane.

So I’m thinking it might be my PC’s configuration that’s causing the problem. First, I tried the latest Nvidia driver (I was previously on 566.36), and it still happens.
So I decided to format the hard drive and reinstall Windows 10. It worked fine for a few days, and now I’m almost certain it’s caused by the latest builds.

Look at the screens below from the dev mode how the RAM and VRAM are NOT saturated

Did you experience this issue before you joined the Beta?
Kinda. It may happens one or two times that since SU 1 released but I’m not sure. It’s started to get way worse since build 1.4.14.

[PC Only] Did you remove all your community mods/add-ons? If yes, are you still experiencing the issue?
Yes,the whole sim was reinstalled without my community folder.

FREQUENCY OF ISSUE

How often does this occur for you (Example: Just once, every time on sim load, intermittently)?

I would say it happens about two out of three times on the latest beta builds.

REPRODUCTION STEPS

Please list clear steps you took in order to help our test team reproduce the same issue:

  1. First, check if I didn’t have any custom doubles sceneries though Dev Mode > Tools > Packages.
  2. Delete everything on AppData\Roaming\Microsoft Flight Simulator 2024 and uninstall/reinstall with Steam and let the sim regenerates the default package without make any change
  3. So at some point I realized that it might be my Setup and Windows that had a problem, so I reinstalled Windows and all its updates. I didn’t have any problems for a while but it just started again.

YOUR SETTINGS

If the issue still occurs with no mods and add-ons, please continue to report your issue. If not, please move this post to the User Support Hub.

What peripherals are you using, if relevant:

  • Throttle TWCS Thrustmaster
  • Joystick Logitech Extreme 3D pro

First, my system is :

  • 5800X3D
  • 4070 Super, with Driver 576.02. Nvidia App is NOT installed.
  • 32 GB RAM
  • 1440p
  • Windows 10 was reinstalled a few days ago.

Options :

  • Vsync 50%
  • FrameLimiter 45
  • FrameGen OFF until I fix that issue
  • DynamicSettings OFF
  • TAA
  • LOD/TOD : 100
  • Offscreen : High
  • RollingCache 64 GB on C:, where MSFS 2024 is installed
  • Raytraced shadows : OFF
  • Volumetric Clouds : ULTRA
  • Texture Resolution : Medium
  • Anisotropic filtering 8x
  • Water Waves : Medium
  • Shadow Maps : 1024
  • Terrain shadows 512
  • Contact shadows High
  • Winshield Effects High
  • Ambient Occlusion High
  • Cubemap reflections 256
  • Raymatched reflections High
  • Light Shafts High
  • Depth of Field : Medium
  • Motion blur OFF
  • Glass cockpit refresh rate : Low
  • Characters quality : Low (don’t really care about the characters)
  • Traffic Airport Quality : OFF
  • Air Traffic : Off
  • Road traffic : low
  • sea traffic : low
  • Fauna : Low

MEDIA

Please add a screenshot or video of the issue occurring.

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[END OF FIRST USER REPORT]

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Do you have the same issue if you follow the OP’s steps to reproduce it?
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2

I also have the same issue

3

Did a little searching and found a couple of options - do you guys have “Citrix workspace” installed on your machine? If so, uninstall it and try again. If you don’t have Citrix on your machine, go into the Nvidia control panel app and find the setting for “Antialiasing - FXAA” and make sure it’s turned off.

4

Thanks for the information, unfortunately, I don’t have Citrix workspace nope, and Antialiasing - FXAA is already disabled in the Nvidia control panel, and can’t be activated anyway in the program settings

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5

In my case RdrThread gets filled up when in VR and looking towards terminal buildings on larger airports, see also VR - Bug in Foveated Rendering related to RdrThread

6

Can confirm this is happening to me too. So annoying.

7

I had great performance in SU1, but moving to the beta early on saw my RdrThread spiking to 250+ and my FPS tanking. I reverted to SU1 and the issues went away so I’m satisfied it’s not an addon, driver or similar issue. Since, SU2 has gone live, and the issues I faced have returned.

With FG, I generally see 60-100fps depending on where I am at with no stutters. I’ve run every graphic settings on highest with exception of motion blur which is off. In SU2 when I spawn in I’m facing very low fps and a render thread that is excessive.

Eventually this does go away, but sometimes only until I move my camera and then it spikes again. This makes it very difficult to play; infact impossible and very frustrating. Sometimes I can get the FPS to remain good and have a good flight fo the most part, but the RdrThread has significant spikes when arriving at the airport I’m landing at, generally just as I’m 50ft above the ground - sim turns into a slideshow and I have a terrible landing.
I would do anything to just go back to SU1 but I know that’s not possible.

I’m on Windows 11 with 7800X3D and a 4090, 64GB DDR5 RAM. Nvidia drivers updated a couple of days ago.

Having found comfort 2024 was running well for me in SU1, I’ve started to enjoy simming more. I’ve recently purchased new hardware to go along with it to improve my experience, but it’s all useless if the sim can’t run. I’m hopeful I can find a solution.

8

Thanks god, i’m not alone.
I spend already more than 1 week for investigation.
Tried everything, even clean full re-install Windows and MSFS.
Tried SU2-beta, SU2, SU3-beta. Nothing help.
And most annoying part:
1 flight from 5-8 attempts - loading amazing good. SAME plane + SAME scenery + SAME date/weather, i have 60fps.
Next free flight loading in same condition - 5-10fps.
I’m just giving up and await some update.

10

Shame you had to reformat Windows just to end up back where you were.

I’m in the same boat. At the edge of doing a full system reinstall but in the back of my mind I’m thinking it won’t actually help and just be a big waste of time.

It’s the sim. Why it only affects some of us is a mystery, which is what is tempting me to do the full Windows reinstall thing.

But I see no one answered the part of the topic title “What is RdrThread”.

It would help to understand it, but according to the GoogleAI_God, it’s undocumented (surprise surprise).

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That summary does point to a core sim software issue though I feel?

11

So, having investigated further…

For me I found my minimum internet speed had dropped. I’m unfortunately in a non-fibre area so connected to an old network on VDSL. This went from 30Mbps down to 19Mbps, and because the whole network is looking to be replaced in the years to come, they won’t send anyone out to fix it. Instead, they offer you an easy exit. The issue is no wired broadband provider has a line to my place except this one kicking out a ‘superfast’ 19Mbps.

So, I bit the bullet and invested in a 5G hub to go alongside my slow internet - as my latency in other games is important I didn’t want to completely ditch the original internet. Having done that, I’ve now seen various speeds around 500-750Mbps through the 5G hub. Ever since I’ve got the Sim to use that particular internet connection, the RdrThread spikes has also gone (Using a program called Proxifier you can pick what network device is used per application etc).

I can only assume there might be some connection between the content being loaded (ie streamed) and how it then ends up in the RdrThread queue? Perhaps it’s queing content that’s not actually downloaded yet, telling the RdrThread “you’re just going to have to wait”.

Someone might be able to tell me they have super fast internet in the sim and might negate my theory, but at least for me, the sim no longer has the stuttering on landing or spawning in initially in the flight where RdrThread spikes and FPS drops since getting faster internet.

12

Can’t be the reason as I have this effect also on Community Folder Airports and after waiting long enough until the Download Speed shows zero.

13

I have a 1 Gbps service and generally hit 1.2 Gbps in testing. With SU2 and now SU3 Beta, I generally have FPS drops when landing.

14

I downloaded almost all addons on su3 beta and now i am at su2, this is only happens when i have an active download starts (observing ingame fps overlay), nothing else. Probably a network driver/Rolling cache issue? At SU3beta sadly even some airports, buildings was increasing rdrthread for me without any downloads active. 7800x3D 4070 32gb Win11 24H2.

15

While lowering settings, most impactful likely resolution, can mitigate this, it really should not be happening on high end systems in a game that uses multithreading.
It is possibly down to poor optimisation of the game engine (multithreading) and some assets and/or people are trying to run the game at too higher resolution and/or graphic settings for consistent frame rates.

However it could be a streaming issue and the CPU is waiting for assets to draw in certain circumstances (Does this still happen to people who have downloaded 2024 core assets?)
Alternatively if your storage device isn’t fast enough that could also cause issues - shouldn’t really be an issue with a modern rig but the faster the R/W of your drive the better (NVMe for the win)

Any system is generally only as fast as its slowest part and CPU bottleneck will kill even a 5090 as the GPU has to wait for the CPU so either wait for a patch and hope it is fixed or lower settings to resolve it (starting with resolution, 4k is very demanding) or look at upgrading the weakest part of your system accordingly.

16

“What is RdrThread” is the key question IMHO. That value is usually ok on my system but if the system chokes then RdrThread is often the number in the in-game FPS tool that has spiked.

As a clue I suspect RdrThread stands for “Render Thread” but there’s no hard evidence for that.

It’d be useful to have a definitive explanation for what dominates the execution time for RdrThread, MainThread, Manipulators, etc, and how you work out the overall frame time from the combination of those numbers. The simplest version of that is choose the larger of the MainThread number or the GPU number but that doesn’t consider the RdrThread/Manipulators/Coherent numbers.

My absolute guess for the RdrThread collapse is that the game is trying to draw stuff, some assets are queued up behind the streaming framework, and that thread ‘pauses’ waiting for those assets to arrive, i.e. the code isn’t async and prepared to continue regardless (which might show artifacts in the 3d world) instead it hits the frame rate.

17

Yes it stands for render thread which is the thread on the CPU that gives draw calls to the GPU among other things.
The more geometry the more draw calls and the draw time (frame render rate.)
the screenshot shows 6.6 fps which means a frame is taking around 150ms to fully render which is also displayed (1000ms/6.6s) - this is being caused by the render thread taking140ms to give the draw calls, physics calc’s etc to the GPU.
The frames will only be drawn as fast as any bottleneck allows.
If you have a low end GPU and high end CPU that will be the GPU but these days most people will be bottlenecked by the CPU.

I mentioned a few possible mitigating factors and workarounds but also I generally try to make the latency of my CPU and GPU comparable (Balanced) which I find gives me much less stutter etc.
So I basically look at how long it takes my CPU and GPU to render a frame and try to balance them with the settings and resolution changes.
To get a stable(ish) 60fps I look to have my CPU and GPU render at 15ms and cap at 60fps.
But because my GPU actually renders at about 10ms I either up the graphic settings or resolution to get closer to 15 which doesn’t hurt my fps.
We should actually adjust our stable fps expectations to the lowest common denominator so if we find our CPU is rendering 25ms and GPU at 8ms we should be looking for a stable 40fps and know we have free headroom on our GPU to up graphic or resolution settings.

Outside of some kind of bug spiking the CPU then Asobo/MS should really be, and likely are, concentrating on optimising the main thread as almost everyone is CPU bottlenecked rather than GPU and DX12 and Vulkan allow for this but as I see it this is not new engine, just the 2020 engine more optimised for DX12 with additional features and you really need to build a game from ground up with DX12 or Vulkan in mind to really utilise them.

18

Just to save people time:
Reinstalling the simulator does not fix this issue.
Reinstalling your operating system with a clean format also does not fix this issue.

Save yourself the trouble and time and wait for Asobo to fix the problem, which may never happen at this rate. Good luck all!

19

Completely agree.
I had amazing performance up until SU2 Beta - either version 1.4.14 or 1.4.16 (can’t remember the exact number).
At that time, I switched back to the SU1 release, and everything was smooth as butter.

But then they rolled out SU2 to the public release with this issue, and it still hasn’t been resolved in the SU3 beta.

This problem is probably the biggest immersion and enjoyment killer in the entire game.
And I honestly don’t understand why it’s not being treated as a top priority.

20

Same here, I stopped trying to rationalize the decision making process – long-time simmer here, with full confidence in their team’s ability to make a good product but I’m getting to the age where I value time actually spent enjoying the product, not tinkering with settings.

If they won’t address it, and if no one from their team can even spare 10 minutes to give a logical explanation as to why the problem even exists, then I can’t be bothered to keep trying. I’ll just wait for them to fix it and enjoy 2020 in the meantime.

Wish I could go back to SU1 as well - did not have the Rdrthread issue at that time,.

21

Same for me!