High VRAM leads to 'overclocking' GPU

Sim Update 2 Beta | MSFS 2024 Beta Discussion
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Although I’ve had generally good performance in SU2, I’ve had occasional bad days and I’ve been trying to troubleshoot this.

I’ve been relying on the devmode FPS overlay, but I’ve noticed that even when everything can look ok in that, there can be stuttering, which often leads to a crash. So I started using the Adrenaline overlay as well and noticed something unusual. When the VRAM has hit its limit, often at a larger airport (even a standard stock one), it has an effect on the GPU utilisation and the GPU boost clock speed.

I have a Sapphire Nitro+ RX9070 with a boost clock speed of 2700MHz. Under most scenarios, it rarely goes beyond that, perhaps up to 2800MHz and the GPU is always at full utilisation of 100%. After the VRAM limit is hit, the GPU utilisation drops, to usually about 80% and the boost clock speeds can ramp up to over 3000MHz, even when the VRAM has settled down to below the limit. I haven’t noticed any increase in power draw, it stays steady at its rated value. This GPU clock speed increase happens on every occasion I’ve hit the VRAM limit and is often followed by a CTD.

Although I’ve sent crash reports to AMD, it would be helpful if others who are having VRAM problems could see if this is happening to them too. To my understanding, the problem I have isn’t necessarily the high VRAM, as this reduces after takeoff, it’s the resultant impact on the GPU speeds which follows this and causes the continuing performance degradation and regular CTDs.

I run Ultra on almost all settings, FSR 3 with frame gen on (full pc spec in profile). No options on in Adrenaline and I haven’t overclocked or altered the GPU at all since purchase. I’ve tried using the optional 25.3.2 Adrenaline driver and the same behaviour occurs.

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That is a peculiar finding. But I think I can safely say that it is not MSFS2024 that is “overclocking” your GPU. In fact, it is most likely the other way around.

First of all, this game, like any other, has no means or reasons to access your hardware directly. So that is not what is happening.

What I believe is happening is this:

  1. Your VRAM is stuffed full by MSFS2024.
  2. Your computer starts using regular RAM or even paging it to disk
  3. This leads to latency penalties since it cannot be accessed as fast
  4. This in turn slows down rendering
  5. Your GPU cannot get the data it wants fast enough anymore
  6. GPU utilization drops, as there is not enough for it to do
  7. Your driver may attempt to boost clocks to maintain framerate or performance
  8. Once the memory stabilizes again, clocks may stay high (due to driver logic), but rendering pipeline is already disrupted
  9. So CTD’s (crashes to desktop) may follow.

I would not alter too much of your settings, either within your OS or GPU/driver, and just wait for Microsoft to stabilize this product first. I’m pretty sure you are doing nothing wrong. This product is just still very rough around the edges.

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Thanks for the detailed reply, what you describe makes sense.

I was concerned because an increase of 300MHz over what is already an overclocked card seemed a bit much and might damage the GPU. I’ll keep the adrenaline overlay on as it’s fairly discrete and monitor the temperatures as well now.

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Interesting - I’ve been noticing something similar with my Powercolor Hellhound Rx 9070 XT.

These are my observations on current MSFS 2024 (not SU2 beta).

  1. My GPU has boost clock of up to 3010 MHz, but while flying in sim it will regularly go past that for extended periods of time (3100 mhz for example).

  2. I have 16 gb vram and it is not the cause (verified in Dev mode) - I’ve noticed during certain times the simulation gets cpu limited (using 5900x cpu), so GPU is waiting and clocks boost to the high values.

  3. Occasionally this has led to black screen crash and reset. Have been mitigating this by reducing board pwr by -5% and reducing max clks by 100 mhz - rather have slightly lower performance than crashes.

  4. Also setting switch of GPU from OC to Silent mode can help mitigate this as it will run in stock speed and not boost so high.

  5. Still experimenting with this situation.