MSFS forums claiming 64GB of Ram helps on 3090s

[Bert Pieke 7,584]

3 minutes ago, Ianrivaldosmith said:

Well using VR I have seen my 3090 up to 20GB of VRAM usage, so I am too also interested in the results. Its due to ship tomorrow, so no harm in trying and if it turns out to be beneficial, then it helps others too. 

I have no doubt that you can use up VRAM... I am not convinced that this somehow gets replicated and stays in RAM... but as you said, lets see what you experience 😉

[RXP 2,336]

I understand many of you doubt my post in the FS2020 forum, and some might not even see any difference if they are under-subscribing their 3090 VRAM. I'm glad someone is reporting his 3090 is only reporting 8GB VRAM use but to me this only indicates he his effectively not concerned with the subject matter.

The post addresses the question some of you using a 3090 and filling its VRAM from FS2020 data might ask: what can I do to make my computer delivering better perf, if this is ever possible with FS2020.

The fact of the matter is that in DX11 and below (as well as OpenGL), this is how this is working regarding memory and resources:

https://docs.microsoft.com/en-us/windows/win32/dxtecharts/resource-management-best-practices?redirectedfrom=MSDN#managed-resources

In short, the DX11 driver implementation is managing the video card resources the application is sending (vertex buffers, textures, Shader code etc...) and can/may keep a copy of what you're sending in RAM in case it needs to send it back later for example. A number of these resources are also kept in RAM most likely for buffers which the application is updating only portions of the buffer data regularly or maybe the contrary, whatever it is the driver sees is better.

DX12 on the other hand doesn't manage memory (like Vulkan) and it is the responsibility of the application to do these things and rest assured it won't change much if the application needs to keep some buffer data around in RAM for the same reasons.

Besides, the way DX11 backs up VRAM buffer memory in RAM is also most likely why you can see Task Manager reporting total GPU ram usage higher than the actual VRAM!

Because VRAM is backed up in RAM by DX11, using a 3090 with 24GB VRAM which is often filled up, you might just want to consider backing this up in the system as well in using 64GB instead of 32GB, especially if the "game" is already taking half the 32GB you have. And although oversubscribing 32GB RAM might come unnoticed at first when using an NVME to store the paging file, it is a hit nonetheless.

PS: the most likely cases in FS2020 you'll experience VRAM pressure is over photogrammetry areas and if you're raising Terrain LOD to 200%. Try it out, low level over London, and see how much VRAM this is consuming. On my 2070S test system I've never exceeded VRAM resources except over the WU3 London, and this shows immediately with several GPU monitoring tools the game is oversubscribing the available VRAM and FS2020 is trying to purge older buffers to make room. During this time the CPU/GPU sync causes the render loop to stall until recovering and until the next few moments afterward it is oversubscribing again.

Edited February 28, 2021 by RXP

[Bert Pieke 7,584]

48 minutes ago, RXP said:

using a 3090 with 24GB VRAM which is often filled up

OK... how exactly do you see this occurring? 

Especially noting: "On my (8 GB) 2070S test system I've never exceeded VRAM resources except over the WU3 London"

I am really missing something here..

Edited February 28, 2021 by Bert Pieke

[RXP 2,336]

1 hour ago, Bert Pieke said:

OK... how exactly do you see this occurring?

I'm currently helping and working with 2 people having similar configs, but different processors (AMD vs Intel), in order to pinpoint what we can specifically push and how with their 3090, when comparing with my test system 2070S. There are multiple goals behind this work which conclusions will be published in "My 2070S Settings" topics, but the main ones are validating some assumptions about the relation to this or that setting with regard to the hardware, and what are the main rendering engine problems holding back FS2020 on such hardware especially in VR. In their configs and in VR, it was not unusual more than 16GB VRAM was allocated either. 

 

[Bert Pieke 7,584]

5 minutes ago, RXP said:

I'm currently helping and working with 2 people having similar configs, but different processors (AMD vs Intel), in order to pinpoint what we can specifically push and how with their 3090, when comparing with my test system 2070S.

I look forward to your findings.. I am sure they will be well researched and documented.

It just seems to me that you were quoted out of context to justify the heading of this Topic "MSFS forums claiming 64GB of Ram helps on 3090s"

which now has eager folks getting their credit cards ready for memory upgrades..

[Glenn Fitzpatrick 3,798]

15 minutes ago, Bert Pieke said:

I look forward to your findings.. I am sure they will be well researched and documented.

It just seems to me that you were quoted out of context to justify the heading of this Topic "MSFS forums claiming 64GB of Ram helps on 3090s"

which now has eager folks getting their credit cards ready for memory upgrades..

Note that the topic said "claimed" and specifically said 3090s.  It was posted to get some discussion happening.  

I am personally a bit sceptical about how much improvement people will see but am keeping an open mind.

As far as cost goes, assuming you are one of those people able to afford a 3090 and matching processor (presumably a 10900K or AMD equivalent) the $US100 or so for another 32GB of RAM if you have spare slots is going to be neither here nor there.

Edited February 28, 2021 by Glenn Fitzpatrick

[knich 113]

Where is the VRAM reading?

[kand 205]

12 hours ago, RXP said:

I'm glad someone is reporting his 3090 is only reporting 8GB VRAM use but to me this only indicates he his effectively not concerned with the subject matter

The most I have seen 2020 use is 11gb VRAM but it nearly always clears out to around 8-9gb, this from the dev mode FPS display? perhaps I should be looking somewhere else? 

I have not been that impressed with my 3090 VGA upgrade and I came from a 1080ti, this was the reason I followed the RAM thread with curiosity. CPU is an i7 9700k @ 5ghz. The main reason I went to a 3090 was for P3D and the DX12 issues, I was also seeing limited by GPU in 2020 regularly. I find P3D is just taking up SSD space these days and seldom used

For the record I run an ultra wide resolution of 5760 using NVsurround over 3 HDTVs so the card is pushing a lot of pixels. 

I most certainly am concerned with the subject matter, or else I wouldn't have shelled out £300 for 2x32gb ! we all strive to squeeze the full potential from our investments. I will follow your work with great interest and thank you in advance for sharing your knowledge. 

many thanks 

 

Edited March 1, 2021 by kand

[kevinfirth 1,392]

On 2/27/2021 at 5:03 AM, G-RFRY said:

So what MSFS needs is a $2,500 upgrade to work best, it was said last year that a sim was coming that would not need expensive upgrades like the other sims 🤑.

Gates' law, flight sims will always be better on tomorrow's hardware 🤣🤣🤣🤣

[Hyperfocal 186]

I'm very curious where users are getting the VRAM usage numbers. It's actually quite a challenge to get accurate numbers given that most software looks at allocation, which is often much higher than actual usage.

[EmaRacing 302]

NO, you can't even use all that Vram on the GPU, basically everything above 8gb of vram is wasted for gaming, let alone 64GB of RAM.

[Ianrivaldosmith 5,317]

22 minutes ago, EmaRacing said:

NO, you can't even use all that Vram on the GPU, basically everything above 8gb of vram is wasted for gaming, let alone 64GB of RAM.

here is me literally just now, in innsbruck in VR 

 

[kand 205]

24 minutes ago, Ianrivaldosmith said:

here is me literally just now, in innsbruck in VR 

 

hmmmm, that's interesting because if I read this correctly windows has allocated 16gb of your system RAM to share with the GPU? This leaves 16gb sys RAM and you are already at 17gb 

what was 2020 reporting in dev mode for RAM usage? 

[RXP 2,336]

35 minutes ago, Ianrivaldosmith said:

here is me literally just now, in innsbruck in VR 

although it won't give you enough FPS, can you try just sitting at EGLC parking, looking toward London Center, and set Terrain LOD 200% and compare? Then just slewing into the center in the middle of the buildings and compare again?

Edited March 1, 2021 by RXP

[Ianrivaldosmith 5,317]

I’ll try these suggestions soon, just rebooting as for some reason msfs is a stuttering mess. Keeps pausing every 2 seconds. Never had this before. Wonder if it’s a server issue