This is an interesting discovery I made this evening.  Any amount of OC on my 3090 GPU via RivaTuner is causing CTDs almost immediately.  I had this happen back in early 2001 when I gave up the sim, and back then, there was an Nvidia driver from late 2000 that continued to work fine with an OC in the sim, but if you upgraded to the latest drivers back then, you would get CTDs consistently and early when loading the sim.  I just ran the older driver until I packed up my cockpit and put it into storage.

Now that I'm back in the sim 18 months later, I was getting the odd CTD, and then I upgraded to Windows 11, and the CTDs starting happening very frequently... sometimes during loading, sometimes during the roll-out onto the runway (if starting with engines running) and sometimes shortly after take-off.  I recalled my experience from back in early 2021, and removed the OC on my GPU, and low and behold, that solved the CTDs.

It's a bit bizarre.  Every other game, benchmark, and stress test I run which uses the GPU at 100% runs fine with the OC... but not MSFS.

I can keep the power setting at max (123% for my Strix 3090) but I have set the clocks at default.  That allows the card to consume more power and achieve max factory OC, but if I try to dial in any more OC myself, it's death by CTD.  I haven't tried more mild OC settings, but I suspect even 1Hz extra will crash the sim. There's something odd going on when you OC your Nvidia GPU with RivaTuner and run MSFS - similar to what was going on in early 2021 - which was clearly something strange based on the fact that a slightly older driver had no issues.  Fortunately, the delta in FPS is only about 5FPS so I can live with it for a CTD-free experience. Maybe DX12 will work with GPU OCing? I will be interested to test it once SU10 drops.

I'm curious if anyone here has experienced this and what have you learned?

MFS is Energy-Savvy !

16 minutes ago, jcomm said:

MFS is Energy-Savvy !

My CPU wants a word... 

It's my experience as well that MSFS doesn't really like overclocked hardware. It also seems current hardware is stock already close to its limits.
Overclocking the 3090 hardly gives you more performance anyway and MSFS is still mostly CPU limited.

I actually undervolted my 3090 slightly. It uses less power and produces a bit less heat that way. That might give it more headroom to run a bit faster too.

Edited August 14, 20223 yr by orchestra_nl

I have found that modern AMD CPUs and Nvidia GPUs are clocked pretty close to their limits as stock and the small amounts you can overclock them only give very tiny performance improvements in MSFS before causing a crash.  I realised some time ago that overclocking was pointless too.

2 hours ago, Virtual-Chris said:

I'm curious if anyone here has experienced this and what have you learned?

First, that with the RTX 3090 it's more useful to undervolt in order to keep it more quiet 🙂

Then, MSFS has no way to determine if you overclocked your card or not. In fact, every card based on the same GPU works at different clocks depending on the manufacturer and the cooling system. The clock also varies with the workload, and this is the cause of your crashes in my opinion.

With other games which are not CPU limited and keep your GPU usage constantly in the 90-99% range, your GPU works basically at one single frequency, and evidently that frequency is rock stable at its respective voltage. 

This is my voltage / clock curve with MSI Afterburner:

You have to think in terms of a curve rather than a point. If your GPU is stable at the highest frequency that you targeted with your overclock, it may not be fully stable across the entire curve.

In the above example, my GPU may be rock stable at 1890 MHz with 0.875 V, but not so stable at 1700 MHz / 0.850 V. And if that's the case and the GPU frequency dropped with a drop of the workload (for example on the ground at a big airport with a complex aircraft and hence severely CPU limited), also the voltage would drop and my GPU could cause a CTD or a freeze even if it's rock stable with every other game which keep it at 1890 MHz constantly.

This doesn't happen of course, because my curve is 100% tested and rock stable since at least one year 🙂

One thing you could do is force the GPU to always work at its max frequency (and related voltage) regardless of the workload, by setting Max performance profile in NVCP, but the best thing to do is optimize the frequency / voltage curve in order to make it stable across all the points.

3 hours ago, Virtual-Chris said:

 I recalled my experience from back in early 2021, and removed the OC on my GPU, and low and behold, that solved the CTDs.

MSFS does not like overclocking.  FYI, I just got a new computer (computer specs is in my signature).  For my new computer, I bought 3600 MHz DDR4 RAM.  Now DDR4 is already an older standard for RAM, because the newest standard is DDR5.  And even for DDR4 RAM, 3600 MHz is hardly the highest clock speed - some DDR4 RAM go higher than 5000 MHz (I don't keep up with RAM news, so I'm not even sure how high the clock speed DDR4 can go to).

I more or less gave the computer store an outline of what I wanted, and they gave me a list to pick the parts from.  The computer store also assembled my computer.  For RAM, they asked me if I wanted to go with DDR5 or DDR4 and I said DDR4 is fine, so they suggested the 3600 MHz DDR4 RAM for me, and I said fine.

Anyways, when I bring my new computer home and I start playing MSFS, and it CTDed quite frequently on me.  I was also playing some Age of Empires 4, and about once out of every 10 games I played, I got a memory error with Age of Empires 4 too.  But aside from MSFS and Age of Empires 4, my computer worked fine.  I even played a lot of Forza Horizon 5, and I never CTDed.  In general, my computer didn't CTD with normal use.

Fast forward a few weeks later, I was not happy with the CTDing in MSFS and the odd CTD in Age of Empires 4.  I ran MemTest on my computer. Sure enough, MemTest found problems with my RAM. I did a lot of reading and digging, and it turns out, the i5-12400, even though it's a very new CPU (Intel just released the i5-12400 this year), the i5-12400 may not work well with DDR4 RAM that is clocked above 3200 MHZ.    

This was baffling to me, that a new CPU, the i5-12400, may not work well with DDR4 RAM above 3200 MHZ.  DDR4 is an old RAM standard, the box of my RAM clearly says 3600 MHZ, and given that some DDR4 RAM can go above 5000 MHZ, I did not consider my RAM to be overclocked at all (especially if I am following what it said on the box of the RAM, which was 3600 MHZ). But I guess my DDR4 RAM is overclocked at 3600 MHZ, because my motherboard's manual had a warning about going over 3200 MHZ for DDR4 with the new line of Intel 12th gen CPUs.

So I lowered the clock speed of my RAM to 3200 MHZ, even though my RAM is rated to go to 3600 MHZ.  When I did this, I passed the MemTest, and MSFS is very stable for me now.  

So in a nutshell, MSFS will push your hardware to its limit and if your computer has any instability at all (ie. because of overclocking), you are more likely to CTD in MSFS than you will with other software or even other games (while I got the odd memory error or CTD with Age of Empires 4 when I was overclocking my RAM, Age of Empires 4 was still way more stable than MSFS).

7 hours ago, Virtual-Chris said:

I'm curious if anyone here has experienced this and what have you learned?

I realised this spending a great deal of time over the last few weeks troubleshooting "memory could not be read" CTDs. I have a factory OC'd Asus 3090. When I remove the OC i.e. reduce core clock by 165MHz, the CTDs disappear.

For me I also had to disable DDR5 XMP as this combined with GPU OC caused these CTDs. But it's 100% reproducible. If I return to GPU OC, the CTDs will reappear, every time. 

Edited August 14, 20223 yr by Cpt_Piett

Odd that people are having so many issues with overclocking, could it be hardware generation specific? Seems like a lot of 3xxx users. All my main components are overclocked, down to manual tertiary settings of the RAM, haven't had a single CTD or error in the sim whatsoever. 

5 hours ago, orchestra_nl said:

.

I actually undervolted my 3090 slightly. It uses less power and produces a bit less heat that way. That might give it more headroom to run a bit faster too.

Same here with a 3080ti. 
Undervolting results in virtually the same performance but with 100-150 Watt less and significantly lower temps. 
 

How do you overclock?

When I set enough voltage the Sim is stable even with overclocking. But you have to ply around quite a bit with Afterburner. 

Edited August 14, 20223 yr by MySound

1 hour ago, Sethos said:Odd that people are having so many issues with overclocking, could it be hardware generation specific? Seems like a lot of 3xxx users. All my main components are overclocked, down to manual tertiary settings of the RAM, haven't had a single CTD or error in the sim whatsoever. 

It’s a matter of luck. For my 3600 MHZ ram, i5-12400, and motherboard combination, it’s unstable for me if I keep my ram at 3600 MHZ. But I read that others with the i5-12400 have no problems using 3600 MHZ ram.

I don't agree with the "MSFS doesn't like overclocking" mantra.

When I built the system in my sig I carefully sourced the components and spent about 8 days tuning it, incl. endless hours of stability tests. Admittedly, I probably scored big in the silicon lottery with my CPU and could probably run it at 5.3 if I wanted to. Now, very very important - cooling. The box I use is absolutely brilliantly constructed, it has 2 180mm fans at the bottom blowing cool air towards the 3090 and I modded the AIO so it has 6 fans in total.

Running Fenix A320 in MSFS in 4k the 3090 lingers between 70 - 73 degrees and the CPU between 40 - 60, mostly Ultra settings, vsync'ed to 30fps. Just finished a flight from PHNL to KSAN, no problems, 5h32m block-to-block.

4 hours ago, abrams_tank said:

So I lowered the clock speed of my RAM to 3200 MHZ, even though my RAM is rated to go to 3600 MHZ.  When I did this, I passed the MemTest, and MSFS is very stable for me now.  

I'm curious how you did this?  I assume you got to 3600 using an XMP profile... did you then just lower the RAM clock to 3200?  What about timings, voltages, etc?  I've been experiencing the dreaded "memory could not be read" errors in MSFS for several months now and I've also got my RAM clocked at 3600 (4x16G of DDR4).  The similarities end there though - I'm running a Ryzen 5900X with a Radeon 6900XT (all stock clocks).  I haven't had a single problem with any other app except MSFS (and it never gave me issues until this past spring).

22 minutes ago, MadDog said:

I'm curious how you did this?  I assume you got to 3600 using an XMP profile... did you then just lower the RAM clock to 3200?  What about timings, voltages, etc?  I've been experiencing the dreaded "memory could not be read" errors in MSFS for several months now and I've also got my RAM clocked at 3600 (4x16G of DDR4).  The similarities end there though - I'm running a Ryzen 5900X with a Radeon 6900XT (all stock clocks).  I haven't had a single problem with any other app except MSFS (and it never gave me issues until this past spring).

The way I did it was to just reduce RAM clock a little. I.e. I had XMP enabled which is 6000MHz for my DDR5. Then I reduced it to 5800 and kept timings and voltages in place. 

With 6000MHz I got lots of errors testing with MemTest86. With 5800MHz - none. 

32 minutes ago, MadDog said:

I'm curious how you did this?  I assume you got to 3600 using an XMP profile... did you then just lower the RAM clock to 3200?  What about timings, voltages, etc?  I've been experiencing the dreaded "memory could not be read" errors in MSFS for several months now and I've also got my RAM clocked at 3600 (4x16G of DDR4).  The similarities end there though - I'm running a Ryzen 5900X with a Radeon 6900XT (all stock clocks).  I haven't had a single problem with any other app except MSFS (and it never gave me issues until this past spring).

For my ASUS motherboard, if you go into the XMP settings in BIOS, there is an option to set the clock speed of the RAM. So I just edited the XMP profile and reduce the clock speed to 3200 MHZ.

I didn't change the timings, voltages, or anything else in my BIOS.  My computer is now very stable, for any video game I play, MSFS included.

Also, if you suspect the problem may be your memory, you should probably run MemTest.

Edited August 14, 20223 yr by abrams_tank