Limited by Main Thread on New High-Spec Build

[Kymedic0215 0]

I realize these posts are a dime a dozen, but I'm at wits end and could use some insight.  I just built a new PC with pretty much top of the line specs (see below).  However, I am still seeing FPS in the 20s on the stock Ultra settings and I seem to be limited by Main Thread.  I really anticipated these specs would handle Ultra with no issue.  I'm not even running full HD.  My current monitor is only 1680x1050.  I also used Ryzen Master in Game Mode with little improvement.  The CPU itself doesn't even seem to be working that hard.  It barely even gets about 55C.  Any thoughts?  TIA.

Ryzen 9 7950X3D
MSI MAG X670E Tomahawk
64 GB DDR5 RAM
MSI RX 7900 XT 20GB
DeepCool LS720 AIO
2TB M.2
850W PSU

[Alvega 2,126]

Look like something is locking your FPS at 20 FPS. Check if Vsync is disabled. 

[Noel 4,563]

1 hour ago, Kymedic0215 said:

I really anticipated these specs would handle Ultra with no issue

Yes of course they will!  Stay with it and locate where the lock is.  NVCP maybe?  I don't know if its lock works for AMD GPU, and also make sure you don't have Vsync enabled at 33% of 60Hz, which sounds quite likely.

[odourboy 1,290]

If it was limited by vsync somewhere, he wouldn't be seeing main thread limited, it would be green. Look elsewhere.

[odourboy 1,290]

2 hours ago, Kymedic0215 said:

new PC with pretty much top of the line specs

Have you run some of the basic benchmarks to confirm your new PC is running at its potential and not being hobbled by something basic like a bus or I/O problem? Or are your issues just with MSFS? 

Edited July 17, 2023 by odourboy

[Alvega 2,126]

12 minutes ago, odourboy said:

If it was limited by vsync somewhere, he wouldn't be seeing main thread limited, it would be green. Look elsewhere.

Not true. It can be green and still say Limited by MainThread, and in his case it probably would since he was running a 7900XT in 1680x1050 resolution.

[cianpars 1,185]

As it's a new build, I would assume mobo, chipset and nvidia drivers are all up to date.  Worth checking the mobo providers website to be sure as windows does not always provide the latest.

After that, make sure that video card control panel settings and msfs settings are defaulted and work your way up from there. 

I also assume that testing is being done with no addons installed and nothing else running in the background.

I run at 1440 with much lower hardware than you with msfs settings virtually maxed out.

Edited July 17, 2023 by cianpars

[Glenn Fitzpatrick 3,799]

Post a screen shot of the in game FPS counter

[Lucky38i 1,110]

1 hour ago, Glenn Fitzpatrick said:

Post a screen shot of the in game FPS counter

This has an inherent vsync and uses resources, I'd advise using another FPS counter. With these specs he's going to be limited by main thread but that's not a bad thing in this situation. @Kymedic0215 You're CPU not working hard is fairly normal. In short you have a workstation CPU not a gaming CPU, the 7800X3D would've been a better choice but at this point that doesn't matter your CPU is more than enough to handle what's going on. It seems like it's not working hard is because MSFS will never saturate all of your cores cause it's not really a multi-core application, yet.

It might be helpful to show your current settings. Also the advise of other comments is very useful.

Also I know it sounds stupid.. but make sure your HDMI cable is connect to the GPU and not the mobo, happens to the best of us.

[Sethos 4,541]

First off, seeing as you're on the 7950X3D, you also need to manage the cores to only let MSFS use the cores with the 3D cache on them. Only on the 7800X3D can you just use it as is.

Secondly, what constitutes "Ultra" settings here, what's your terrain level of detail etc. We just had a thread where someone had similar complaint that went on for a long time. Turned out he just cranked terrain level of detail past 200, which is extremely demanding, in built up areas and with AI and that's when you start to take a hit.

Even with a high-end machine, you cannot max out every slider, not even with frame-generation, which you don't even have access to.

[Poppingcork 24]

1 hour ago, Sethos said:

First off, seeing as you're on the 7950X3D, you also need to manage the cores to only let MSFS use the cores with the 3D cache on them. Only on the 7800X3D can you just use it as is.

Secondly, what constitutes "Ultra" settings here, what's your terrain level of detail etc. We just had a thread where someone had similar complaint that went on for a long time. Turned out he just cranked terrain level of detail past 200, which is extremely demanding, in built up areas and with AI and that's when you start to take a hit.

Even with a high-end machine, you cannot max out every slider, not even with frame-generation, which you don't even have access to.

Curious:  do the Ryzen 7 chips do the same?

[Sethos 4,541]

9 minutes ago, Poppingcork said:

Curious:  do the Ryzen 7 chips do the same?

Not sure I follow, what specific Ryzen 7? As that's a moniker that is used in both their 5000, 6000 and 7000 series of chips. But what I said only goes for the 3D V-Cache chips. The 7900X3D and 7950X3D doesn't have the V-Cache available on every core, thus you need to make sure MSFS only uses the cores with that cache available, for best performance.

With the 5800X3D and 7800X3D, there's 3D cache on every core, thus you don't need to worry about it.

[Poppingcork 24]

20 minutes ago, Sethos said:

Not sure I follow, what specific Ryzen 7? As that's a moniker that is used in both their 5000, 6000 and 7000 series of chips. But what I said only goes for the 3D V-Cache chips. The 7900X3D and 7950X3D doesn't have the V-Cache available on every core, thus you need to make sure MSFS only uses the cores with that cache available, for best performance.

With the 5800X3D and 7800X3D, there's 3D cache on every core, thus you don't need to worry about it.

Perfect.  Thanks!!

[Ianrivaldosmith 5,317]

18 hours ago, Kymedic0215 said:

MSI RX 7900 XT 20GB

May I ask, why? 4 series gives you FG. 

[MySound 408]

Well. For almost every game there is a main thread. You use threads to distribute work. However, one thread is holding it all together. You can’t distribute one thread to multiple cores. And though the 13xxx and 7xxx CPU are strong overall, the single core performance did not grow as much over the last years. 
And, together with the Terrain LOD set to high leads to main thread limitation. 
 

And I am 98% sure that’s the case here too. 

Edited July 17, 2023 by MySound