I’m reporting a performance issue in Microsoft Flight Simulator 2024 that appears to be related to the internal memory budget (“AllocatedMem”). I’m also posting this to see if other users have experienced similar symptoms.
My setup:
Ryzen 7 9800X3D
RTX 5080
32 GB DDR5 @ 6000 MHz
3 × 1440p monitors (separate viewports)
Fenix A320
Photogrammetry ON
EGKK by iniBuilds
Real weather using REX Atmosphere
No multiplayer, no AI traffic, no in‑game traffic
Flying on SayIntentions.AI (ATC only)
Observed behavior:
With 2 monitors, the sim stays close to the AllocatedMem limit (~30 GB) but remains playable.
When enabling the 3rd monitor, AllocatedMem immediately reaches ~32.4 GB, and the sim becomes almost unusable: heavy stutters, memory purges, FPS collapse, delayed terrain loading.
Clarification:
AllocatedMem seems to be an internal memory budget of the FS2024 engine, not the physical RAM of the PC.
Even with 32 GB of DDR5 @ 6000 MHz, system RAM usage stays well below the physical limit (typically around 20–25 GB depending on the situation).
So the system RAM is not saturated.
This raises the question: is the internal AllocatedMem ceiling (~32.4 GB) being reached when using 3 viewports?
To help investigate, I generated TWO RAI Archives:
One RAI with 2 × 1440p monitors → close to the limit but still playable.
One RAI with 3 × 1440p monitors → AllocatedMem reaches ~32.4 GB instantly and performance collapses.
Both RAI Archives and the ConsoleLogs file have already been submitted to Asobo through a Zendesk ticket for internal analysis.
If anyone else has seen similar behavior with multi‑monitor setups, I’d be very interested to hear your experience.
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To help compare memory allocation, below is a screen shot I took a month ago with the MSFS FPS overlay on while using triple screens (screenshot is of main screen), in the default A330-200 over NYC in SU4.
I’m not sure, but I think you are correct, there is some artificial limit to memory usage, but, I think CPU is the bottleneck, not the RAM. Just my guess. Also, are you just looking at how much RAM MSFS is using, because, Windows and other tasks need RAM too…
System specs
9800X3D
RTX 5090
96 GB 6000 CL28 RAM
Triple 4K TVs, in MSFS are set up in a 2K - 4K - 2K configuration.
I had also tuned my system which has a huge effect on memory efficiency: EXPO, tighter memory subtimings, PBO Curve Offset -13, +100 MHz Boost Clock.
I only use one 1440p monitor, but I have spent quite a bit of time, testing the allocated RAM in MSFS2024, as I run into problems in certain situations, with only 32GB installed. System heavy aircraft, hi res textures (heavily affected by the texture resolution slider in the sim), TLOD and the off sceeen pre caching are very important factors to how much RAM your sim allocates. Having a 3rd monitor active, increases the amount of scenery being loaded dramatically, so no wonder, the RAM usage goes up. Once, it surpasses the 32GB, the data that needs to get loaded go into the swap file (the page file should be set correctly in Win11). That means, essential data are now on your SSD, instead of the RAM, and since the read and write speeds are a lot slower on the SSD, compared to the RAM, the CPU gets hammered, and the sim becomes sluggish, stutters, and can crash to desktop. So I guess, upgrading your RAM to 64GB, or reducing the mentioned settings significantly is the way to go for you.
Thank you to everyone who responded so quickly to my question. I truly appreciate the time you dedicated to testing, comparing, and sharing your impressions.
In the video I posted, you can clearly see that my physical RAM is not at all saturated. For this test, I only used the EGKK scenery (iniBuilds files), and ChasePlane from Parallel 42. I didn’t enable SayIntentions or AI traffic during this recording, which explains why the allocated memory doesn’t reach the usual limit. If needed, I can record another video with SayIntentions and AI traffic enabled so you can see the difference.
The video clearly shows that my RAM usage doesn’t match the allocated memory in my case. The RAM remains well below 32 GB, the swap file is never used, and the system remains perfectly stable. However, everything related to FS2024 (likely due to the game’s streaming system) behaves differently when I use demanding avionics like the Fenix A320, combined with photogrammetry and a three-monitor setup.
This is where the problem lies: the three-monitor mode with separate windows is not optimized and struggles even on high-end hardware. NVIDIA’s tools and drivers also don’t seem to be fully adapted to FS2024’s multi-window rendering, which exacerbates the situation.
In my case, the problem isn’t due to RAM saturation, CPU limitations, or GPU temperature. The only bottleneck I consistently encounter is allocated memory, and this only occurs when using three independent windows with a complex aircraft and dense scenery.
Thanks again for your help and for this constructive discussion. I can provide further tests or another video if needed. triple screen
I tested this a while ago ( videos still on my YT channel). 64gb - Single screen going over 32gb in heavy urban areas, but with triples - urban areas i remember seeing 38-40gb. (With High terrain settings).
32gb RAM - i had stutters with 28-29 usage at urban areas single screen. Acceptable performance with 40gb allocation in hawaii (default game no addons).
The numbers of course goes up more with background stuff or addon’s.
Thanks for the clarification, AOZ67. Indeed, I do need to upgrade my RAM to 64 GB.
I thought FS limited RAM, but I’ve seen other videos where the problem was less noticeable with more RAM, especially since three 2K screens have about 11 million pixels, which is enormous for this simulation.
I’ll wait until the current absurd RAM prices come down, if that ever happens.
