A350 - SU4 - Severe performance issues

[DarrianCZE]

Hi, I have decided to give SU4 a try and I have noticed that with version 1.1.6 the aircraft performance leaves a lot to be desired. I am currently in the cruise level and I am getting a mere 35 FPS. According to the Dev mode, the Main Thread is seriously overloaded. I have tried reducing the settings but nothing changes that.

And with the same settings, I am getting around 60 - 70 FPS with other addons like FenixSim A320, etc. After updating to SU4, I have also completely re-downloaded the aircraft from scratch and removed a350 from WASM folder in Appdata. So this is basically a clean install of the plane.

As you can see in the screenshot, there is no VRAM overflow (I have 24 GB) or anything else obviously wrong.

My hardware is also not fully loaded:

Therefore I am quite certain this is not a hardware or configuration issue, and the issue lies somewhere in the A350 itself.

[DarrianCZE]

Also my temperatures are also fine:

 

[DarrianCZE]

And I am starting to think that there is some issue with the Cabin Pack, because if I move my camera into the cabin, and even just looking out of the window, the Main Thread overload gets significantly worse.

Virgin Atlantic Cabin

[frank_m]

Surprisingly, I discovered a far better performance with 1.1.6 and SU4 1.6.11.0. The experience was much smoother than in SU3 or before 1.1.6. I use the A350-900 with Lufthansa Cabin and Livery.

[tjockklat]

For me i get way better performance in SU4 compared to SU3 with every aircraft.

[DarrianCZE]

Me too. Just not in the A350. I have just flown 77W today, and I had smooth 60 FPS (without FrameGen!) for the entire duration of the flight.

Edited October 12 by DarrianCZE

[DarrianCZE]

Looks like I might have solved by problem. But it's just a test on the ground, so it's not conclusive. I will tell more once I will have time to perform a full flight.

I have deleted all aircraft folders, including one which I haven't deleted before.

1) I have uninstalled the plane in iniManager including all cabin packs

2) I have deleted following folders:
- Community\inibuilds-aircraft-a350
- AppData\Roaming\Microsoft Flight Simulator 2024\WASM\MSFS2024\inibuilds-aircraft-a350

And this is a new one, which I have not additionally tried before:
- AppData\Roaming\Microsoft Flight Simulator 2024\SimObjects\Airplanes\A350

3) Then I have installed the plane again via iniManager and done the test

FPS seem far better now. 40 - 50 FPS without FG on the ground

[frank_m]

In the simobjects folder only the state and the camera configuration is stored. It has definitely no influence on the performance. 

[DarrianCZE]

Weird. Maybe something got fixed in the latest SU4 beta, or I am having a placebo.

[Eddie]

The beta is a beta after all. Important to note that one version of the beta may function perfectly while subsequent versions may not and vice versa. Your "placebo" may very well be not a placebo. 🙂

[Akashpnair]

On the latest build of SU4beta( as of today), installed the Airbus A350 ( with cabin pack 1 and 2), and the performance was horrendous. All other aircrafts work well, except the A350.Since launch, the A350 is the only addon I have issues with playing on both 2020 and 2024. Its hardly flyABle with heavy performance issues. I have smooth performance with all other addon aircrafts including the Fenix, PMDG 737,777s, ifly737MAX and also other inibuilds A300-600, A340-300 as well.

Even in MSFS2020, the A350 isnt flyable and multiple users have reported this issue. Same for the 2024 (lets say this sim is still in development with SimUpdates coming and going, but what about the 2020?)

This is not just a system issue but inibuilds need to fix performance issues with the A350. Despite having multiple updates to the a350, its still isnt optimized yet. 

Regards,

Akash Prakash

[CaptainJac]

On 10/15/2025 at 3:41 PM, Akashpnair said:

On the latest build of SU4beta( as of today), installed the Airbus A350 ( with cabin pack 1 and 2), and the performance was horrendous.

Same here. Absolutely HORRIBLE performance sitting on the ground at Inibuilds EGLL. I have a 5090 and 9800X3D, so close to the best computer you could buy. The stuttering is absolutely horrendous and it's pegging my mainthread constantly at 100%. Also in SU4. I will try a full clean install one last time, but if that does not work, this plane is going right back into the hangar where it's been sitting for months anyway due to horrible performance. 

Edited October 20 by CaptainJac

[91868]

I used 350's low-resolution textures. After that, I got a relatively high frame rate of 35 to 40 fps in the cockpit. However, when I entered the cabin, the frame rate would suddenly drop to single digits. Maybe the performance of the cabin is the main factor affecting the overall performance of the 350. The external view is not ruled out.