(NDU registry change) Increase performance immediately! AMAZING!

Post updated 08/10/22

I just tested this 08/10/2022 the NDU change. There is no longer any difference! Probably following a Windows or MSFS update.

This change instantly improves sim smoothness, not just delete descrease performances.

Hello friends, sorry for my english, i’m belgian and i speak little bit english :slight_smile: I use google translate for my explication.

My configuration:
Win11 - Ryzen 9 5950X - Geforce RTX3090 - 32GB

My settings after applied this solution:
ALL in Ultra in MFS and ALWAYS 60 FPS around the world

I’ve been flying FS2020 since its release. 1 year ago I bought a great PC and the sim is not fluid. At each start of the flight, the sim is fluid and beautiful. Over time, simulation performance decreases. I tried everything for almost a year and no solution! Many simmers have the same problem.

Today I found the solution and the result is impressive!!

The sim has become much more fluid and piloting has become a real pleasure.

I made 1 change in the Windows registry (step number 8 in the link below).

I made this change 24 hours ago and since then no crashes or problems. To see in the next few days.

Other simers have made this change and have the same result!

8 Solutions pour réparer l'utilisation élevée de la mémoire & CPU – EaseUS

Ndu In Registry (default 2, change to 4)

Resume in english:
Disable The NDU Registry

1. Open the Registry editor app (Regedit) again and navigate to HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Ndu.
2. Find and Right-click on the Start option and click on Modify.
3. Change the value from 2 to 4 and click on OK and reboot system.

Now the sim and result is WAW! I directly saw a very big difference in fluidity.

  • If you test, write your review for community sharing please :smiley:

Sorry for my english.

Have a good flights friends :slight_smile:


I confirm! Before making this change, my sim was at 70% options with slowdowns. After, I was at 100% options with no slowdown. It’s incredible!


Can I just confirm? Was it " Method 8. Disable UDN in the registry" you did?

Yes :slight_smile: I only changed that!

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Google: Disable Ndu In Registry On Windows 10

If you needed English version.

NDU is how it translates not UDN

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Hmm. interesting… Here is the english version:

Disable The NDU Registry

  1. Open the Registry editor app again and navigate to HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Ndu.

  2. Find and Right-click on the Start option and click on Modify.

  3. Change the value from 2 to 4 and click on OK.

  4. Restart Windows

NDU stands for Network Diagnostic Usage. It basically monitors the network data usage.

Why is it related to MSFS?
Because in MSFS Data settings, you can see that there’s a Data Consumption and Limitation feature. Somehow MSFS is using and connected to Windows’ NDU to monitor the data consumption. As you already know that MSFS is constantly downloading data from the cloud during flights.

Why disabling NDU may make MSFS smoother and more fluid?
Because most probably there’s a bug on Windows’ NDU (e.g. memory leak or process leak) which affects MSFS performance.


Will try! I’ve given up trying to fix the issue
Loading in now, I should see CPU Mainthread degradation within the first hour so :crossed_fingers:

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I don’t know if it’s a miracle solution but it works with my computer. :crossed_fingers:


You’re playing at 20 FPS? 20 FPS is hard on my eyes and gives me a headache.

Although I guess the 20 FPS setting is actually refresh rate divided by 3.

When the 20IPS option is active, the sim still displays 50IPS (developer mode). I don’t know why BUT by activating 20FPS, the movement of the camera is smoother. If I put 20-30 or 60FPS, the sim always runs at the same number of FPS… :rofl:

I see. I made a edit to my last post. The FPS limiter option depends on your refresh rate. 60/30/20 is actually 1/2/3 divisors.

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basically, the ‘FPS’ numbers shown there are based on a 60Hz screen.

so ‘30FPS’ means ‘50% monitor refresh rate’, and ‘20FPS’ means ‘33% monitor refresh rate’

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Ok I didn’t know thank you :slight_smile:

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No wonder, it’s really a bad way of naming the setting in the sim :slight_smile:


Maybe this is the service MSFS uses to keep track of its data usage. In the registry, 2 means automatic start, 4 means disabled.

I don’t think I fly long enough sessions to run into that performance degradation issue, but I will try anything if it can help reduce the CPU bottleneck :wink:

First test - Default A320, engines running on a runway.
1 HR completed and the main thread has remained at 12ms, usually by now I would have seen the main thread timings increased.
Will now test with FBW. Don’t want to get carried away yet, as there have been times before when I thought I had resolved the issue only to find the performance drop later.

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Good luck to all who try it.


Smth is wrong with FBW after SU8 - performance decreasing (FPS drop) during flight (3/4h).
I completed 4h flight with CJ4_WT and I had no issues.


It is in need of optimizations


Yeah your correct
Second test in FBW and within an hour MainThread increased from 16ms to 18ms green to yellow

I only fly the FBW for long flights so had assumed the problem exists with other aircraft

Will now leave the default 747 on overnight and see if that sees any degradation