Limited performance in 4K with I9 10900 KF and RTX 3090


I’m having some performance issues on MFS.
I have an i9 10900KF processor, an RTX 3090 graphics card, 64 GB of RAM and MFS is installed on a SSD.

I play in 4K definition (3840x2160) with all the options in ultra. I thought that with this processor associated with the graphics card the performances would be much better. I read on this forum that people with good configurations also encounter this kind of problem.

In large airports or low fly over very big cities, I am generally (depending on the type of aircraft and with cloudy weather) around 22-30 fps, in medium airports or flying over medium density areas I will reach 30-40 fps and finally in desert areas or at high altitude I am around 50-55 fps. When I see some youtube videos with a similar configuration reaching 50-60 fps over dense cities I don’t understand…

Do you have any idea ?


Did you change render scaling? (leave at 100%, or better yet, lower it to 70/80% if you’re running on 4K).
Did you increase the glass cockpit refresh rate? If yes, stick it back on medium, or even low.

If you want to find out what’s holding you back, turn on developer mode for a bit, and use the FPS statistics from there. That way you’ll see if you’re CPU or GPU limited, so you can target the correct settings to change.

1 Like

Thanks for your quick answer MortThe2nd.

Yes ther render scaling is 100% (when I lower at 80 or 70% the frame rate is better but what I understood is if I want to play in “real” 4K I have to leave render scaling at 100 %)

I didn’t decrease the glass cockpit refresh rate (i’m gonna try).

I’ve already switched into developper mode but sometimes it’s GPU limited, sometime CPU limited ;-).

So I’m surprised to have to lower some options in 4K with such a processor and GC…

20-30 FPS gives you smooth flying. Are you unhappy with how the simulator feels right now?

The 10900k(f) is a 10 core / 20 thread CPU. There is currently no game (or sim) that fully utilizes all those cores, and likely there won’t be in the coming 5-10 years). These CPU’s are more suited to heavy productivity workloads (like rendering or video editing). You could take the biggest Threadripper CPU you can find (64 cores / 128 threads, around 4000 dollars), and it will actually perform worse than your 10900kf. All those extra cores/threads don’t help past a certain point (6 cores / 12 threads), and are basically wasted because they were not designed for a gaming workload. Throwing more money at the issue simply doens’t help past a certain point.

About the render scaling; while technically true (about the ‘true 4K’), if you can’t see the difference on your display, does it really matter if its ‘true’?
Just give it a try.

1 Like

@PIC4506 : you’re absolutely right 25-30 FPS is smooth enough for flying :wink: (but as I said I’m surprised when I see other people with same proc and GC reaching 50-60 fps)

@MortThe2nd: thanks a lot for your explanation about processor. And I agree with you for the “true” 4K . The most important is what I feel :wink:

I have virtually the same setup as you but overall don’t see high FPS rates above 35FPS.
I have 32Gb memory clocked XMP @4000.
What type of memory do you have?
Many people focus on FPS but the key question really is does the flight look good and smooth to you? If it does, don’t ■■■■-yse over the FPS.

1 Like

I’ve been using flight simulator for decades and have always chased FPS. It can be very addicting, trying to get the most frames. Back in the day the frame rates were much lower than can be achieved with GPU’s available now.
The best advice I can give is stop trying to max out frames per second and focus on 1- how does the aircraft “Fly” (smooth, little to no lags), 2- Does the simulation environment look great.
The developer mode can be a good guide to see what settings tax your system. If you are in the low teens routinely, then back off some settings. Ultimately turn off the FPS counter and go Fly. Don’t spend more time tweaking settings, take to the skies!


have a quick read through this…

Quite honestly, it really doesn’t matter what beast you are running on, like Mort said. There will always be some compromises required to get the high frame rates. It is a balancing act at best. Once it feels good to YOU and your flying is not being affected by frame rate, fly on.

Some good tips here…

and here…

1 Like

I have 64 Go memory XMP @3200 MHz

Everybody you’re right ! I stop focusing on fps (everything is smooth enough for me and there’s no lag) and let’s go flying :grinning:

1 Like

Like any disease… The first step is admitting the problem… :grin:

Dang…I was just going to suggest you send me that card to see if I could nail down the problem with!!