Coherent has a MASSIVE performance impact on FS24

Yes, a fix will be included in next week’s update.

Best regards,

Eric / Asobo

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Hello @Vantech

Some changes were introduced with version 1.2.7.0 in that regard.
Can you confirm the improvement?

Regards,
Sylvain

Massive improvement, thank you.

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As of today there still seems to be a substantial difference in CoherentGT performance in MSFS2024 vs MSFS2020, i.e. x2 or x3 faster in MSFS2020?

You can pause this video pretty much anywhere and see that in the FPS debug info:

Here we go… After weeks of normal operation, after today’s update (1.2.11.0) we are again stuck at 68%, in the last stage of product testing before launch. This is nightmare.

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The same on one of my two machines

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FIY Miltech is a first partie dev

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We continue getting reports from users indicating that Coherent still has a disproportionately high amount of resource utilization on their end compared to FS20, being this the main source of low performance on the C17.

Though the first set of updates did improve the situation, resource utilization continues to be quite high.

@erasam Has your problem been resolved?
Here on my side, the problem was resolved using the Riva Tuner software to limit the Sim’s launcher to 30fps every time it starts. After the loading screen, I can return to the 60fps setting and use it without any problems.
It’s also important to say that installing Windows 11 didn’t solve the problem, as did clearing the cache or other things. Only Riva Tuner solved it.

@FlyingRaccoon Just a bump, since the release of SU1 we have had many users reporting this issue again, on both PC and Xbox

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Bump @EPellissier @FlyingRaccoon - Issue persists in SU1!

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Updates on this? Is the team aware that while this was initially fixed it has broken again in the latest Sim Update Betas?

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Anyone know if it’s possible to check the relative performance of the multiple html/js instruments in the Coherent Console to see which one is consuming the CPU ? Currently I’m unsure if it’s all html/js code in MSFS2024 is running significantly less efficiently than in MSFS2020, or it’s additonal core-sim JS in 2024 that’s bumping the numbers up (probably both).

E.g. there’s something in the XML-gauge Asobo Cessna 152 using significant CoherentGTGUI time (on my Intel 12900K) and it would be interesting to know what it is. The EFB app wasn’t open when I did the screenshot but maybe it consumes resources even when not used.

My planes have a lot of html gauges so if anyone knows how to break down the Coherent numbers in the FPS tool between the different gauges that would be useful to know. My current method for my own gauges is to temporarily no-op the ‘Update’ method of my BaseInstrument sub-class and see whether some high CoherentGTGUI usage goes away - this works ok when I already have a healthy suspicion for the culprit, like the Leaflet map move in 2024, but it doesn’t help me find the problem in a large set of gauges.

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Hello @FlyingRaccoon
Any word on this? Didn’t see it listed on SU2 Beta

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There is something like a 3x change in the html/js load for the same plane MSFS2020 to MSFS2024.

If it was 10%, maybe this could be considered just some change to the code between sims, not much of an issue to worry about.

But 3x ?? Surely that should be recognised/flagged as something has gone a bit awry with html/js support in MSFS2024?

Every independent reference I come across reflects the same issue. Most recently see

where the streamer runs the SAME plane in 2020/2024 to test his graphics card, not really looking the the CoherentGT number but capturing it in his screenshots.

Pause video at 1:40 (MSFS2020) CoherentGTUI thread is around 1.5 ms.

Pause video at 2:00 (MSFS2024) Same is now 5.5 ms.

Every similar independent comparison on youtube seems to show the same thing.

The html/js system is inherently relatively high overhead so careful coding is essential, but the MSFS code in that framework is expanding rapidly in MSFS2024 so it really needs a lot of attention. The 3x load shift should be triggering alarm bells. Is it the platform running more slowly, or is there inefficient additional code outside the planes which is now loading the system during a flight? How could we tell?

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We can confirm the 3x-4x difference. We have an debug version of the aircraft in FS20 that we’ve been using to quantify these performance differences and have managed to consistently replicate a 3x-4x increase in CoherentGTUI.

This can also be observed in the impact GLASS COCKPIT REFRESH RATE has on FPS, particularly in lower-end hardware.

Very problematic for xbox, as the lag spikes on the C17 (directly attributed to Coherent) are affecting the user experience.

And this is on an aircraft that heavily relies on WASM avionics, 5.5ms is still very manageable.

The impact becomes a problem in aircraft that rely exclusively on Coherent gauges (53ms on the C17! vs. 11 in FS20, both ultra settings).

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With the A32NX and glass cockpit refresh high, a fairly heavy JS plane with around 160k lines of typescript + msfs-sdk, react, etc.
MSFS2024:
Screenshot 2025-03-30 224302
MSFS2020:
image

I am not 100% sure these timers are measuring exactly the same thing between the two sims though.

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Hello @EPellissier @FlyingRaccoon
Wondering if this is being looked at for SU2, or will be SU3+ fix?

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