investigating Stutters with radar altimeter ON

[iceman06]

Hello dear pilot friends,

I'm posting here because I think I've discovered a rather disturbing problem on the viper, I haven't found any other post mentioning this but this may be explained by the fact that if other people have a similar problem, they haven't been able to establish the origin. As the title indicates, these stutters occur when the altimeter radar is active, this is easily reproducible when I perform a dive or roll climb below 5000 feets. (See Track files)

I was flying Hornet and recently switched to Viper, so I can't know if this problem appeared with an update or something in my computer configuration or if this is reproducible to other people. What I can say with almost complete certainty after having looked into the problem for several weeks and having tested almost every possibility of adjustment, is that the problem only occurs on the Viper among the other planes that I own (Hornet, Mirage 2000, F-15 FC3..etc)

I first started by completely reducing my graphics options, tested different nvidia settings, tried different power plans, with and without HAGS, disable full screen optimization, disable core parking, add exclusions to windows defender, set high performance options in windows display settings, repair DCS, Clear all shaders caches, game and direct X, Disable hot plug, disable usb selective suspension but nothing was able to remove these stutters.

After trying all these solutions I looked into the various electronic systems of the Viper and that's where I was able to understand that deactivating this simple switch solved the problem.

With my current settings I was able to eliminate 98% of stutters for which I was able to determine an origin, 1% still remaining unexplained to me but only very rarely occur randomly and do not constitute a serious problem, remaining 1% that I can with certainty attribute to the ALT Radar of the F-16C.

I can reproduce the problem on each map that I have, whether in a quick mission or via the mission editor, but my most convincing tests are taken from "Free Flight" on the Gulf map, you will be able to see by looking at the track that I release my load to go to cat 1 and give more agility to our bird.(Sorry if there were pedestrians down there)

It would be interesting to know if other people are able to reproduce these jerks under the same conditions as me to determine if this problem deserves a correction from the devs or if unfortunately only my configuration is responsible.

I'm certainly forgetting things to add so don't hesitate to let me know. Otherwise please excuse my English google translate but unfortunately this is my only way of communicating with you

 

Despite its 5 years, my PC configuration with my settings still holds up quite well on DCS

 

Configuration :

Windows 10 22H2, Intel I7 10700K, Asus Z490-E, DDR4 32Gb (2x16Gb) G.skill Trident Z 3600Mhz, Rog Strix 3060Ti, Nvme SSD Samsung 970 Evo plus 1Tb, SSD Samsung 860 Pro 1tb, SSD Samsung 850 PRo 256gb, Asus PG279QM 240hz G-Sync, Hotas TM Warthog + Viper TQS Throttle.

 

Nvidia Drivers and Panel settings :

-566.03 (Old driver but which works very well for me (I am one of those who do not update if it is not broken especially since Nvidia missed the latest drivers)

-Low latency mode: ultra

-Power management mode : Prefer maximum performances

-G-SYNC : ON

-V-SYNC : Use 3d setting and OFF in game (Better for me on DCS)

-Shaders cache size : 10GB (unlimited tested too without any changes)

 

Windows Settings :

-High power plan

-Game Mode : ON ( tested OFF also )

-Game bar : OFF

-Hags : OFF

-Full Screen optimizations : Unchecked

 

Among the attached elements you will find the comparison between Radar Alt On and OFF, I have also attached the use of my processors on msi afterburner because I suspected that radar alt led to a more intensive use of the cores when activated but by comparing this does not ultimately seem the case, the two seem similar... (?)

 

Thank you for reading, I look forward to your feedback !

ViperStuttersRDRaltON.trk ViperStuttersRDRaltOFF.trk dcsRDR_ALT_ON.log dcsRDR_ALT_OFF.log

DxDiag.txt

Edited May 12 by iceman06
Things to add

[BIGNEWY]

Hi Iceman, 

sorry to see you are having issues, can you also attach your dxdiag so the team can take a look 

thank you 

Logfile Analysis
DCS Version 2.9.15.9599
Edition Standalone
OS-Version 10.0.19045
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
CPU
Intel(R) Core(TM) i7-10700K CPU @ 3.80GHz
[1x L3 caches]
Cores / Threads
8/16
 
RAM
32669 MB
Pagefile
8704 MB
Preload Radius
30000
GPU
NVIDIA GeForce RTX 3060 Ti

Advice
 
Change your pagefile to at least 32768 MB (initial size).
Windows 10 will be EOL Oct 14th 2025. Upgrade to Windows 11.

Verify that this is configured correctly in Windows:
Game Mode disabled
Hardware accelerated GPU scheduling disabled

Tuning Tips
 
Enable Full Screen mode.
Tuning tips are recommendations for better FPS based on your CPU, GPU and RAM.
They might result in slightly decreased display quality.

[BIGNEWY]

Thank you for the dxdiag

Drive C :
Free: 266.5 (27.96%)
Type: Samsung SSD 970 EVO Plus 1TB
Drive D :
Free: 974.5 (99.76%)
Type: Samsung SSD 860 PRO 1TB
Drive E:
Free: 139.3 (57.04%)
Type: Samsung SSD 850 PRO 256GB

Check your D   C drive it is very full and can create performance issues if its being used for DCS

The dxdiag also hints at some memory timing issues, are you using XMP or manually overclocking your RAM? 

 

[iceman06]

 
@BIGNEWY Hi and Thank you for your answer !

 

I attached my dxdiag with the other files in my initial post, I also set my paging file manually to 32768MB.

(Page file was set in auto because Red Dead Redemption 2 crashes when set manually, Game mode and hardware scheduling was also tested ON/OFF, Full screen is set and no changes) 

Concerning Windows 11, I am still hesitant to come to it but I know that I will soon no longer have this choice if DCS locks updates for W10 in the future...

The Viper is my only module causing this problem. After some additional research, I found two posts similar to my problem that date back to dcs 2.5 and were fixed with an update.
Later a member reported the problem having returned to 2.7 but without having more details 

Post 1 :

Post 2 :

 

 

 

 

Edited May 12 by iceman06

[BIGNEWY]

Hi, 

the above issues were fixed some time ago. I have tested today using your tracks and I am not experiencing the stutter, I will ask others to check also so its not just my machine being used. 

[iceman06]

Have you tried to reproduce the exact same path and movement as in my track?

To respond to your previous post, my D disk is completely empty, I only store old secondary games on it.
I also disabled XMP to test if the problem was there but no change the stutters occur with the radar altimeter and disappear when the switch is OFF.
One avenue could then be the Nvidia 566.03 driver. I admit that I have not tested any other driver since..

Edited May 12 by iceman06

[Gryzor]

6 hours ago, BIGNEWY said:

Hi, 

the above issues were fixed some time ago. I have tested today using your tracks and I am not experiencing the stutter, I will ask others to check also so its not just my machine being used. 

Maybe stuttering after high fps like 120 vsynced or so.... and not with vsync 60Hz whick CPU spikes are less noticeable. Or maybe with vsync off those stutters are not so abrupt... what is you testing condition?

[iceman06]

43 minutes ago, Gryzor said:

Maybe stuttering after high fps like 120 vsynced or so.... and not with vsync 60Hz whick CPU spikes are less noticeable. Or maybe with vsync off those stutters are not so abrupt... what is you testing condition?

This is a good question because I didn't specify it in my message,
I tried several settings whether G-Sync + Vsync On/OFF, Fps cap: Without / 240 / 145 / 120 / 100 / 60 / 30
I even tried several monitor frequency adjustments without success. 
Indeed, as you mention at high fps, some stuttering can occur, but in my case, even with a heading of 30fps or 60fps, these high spikes appear when the Alt radar is activated during climb, dive and roll maneuvers.

Edited May 12 by iceman06

[BIGNEWY]

15 hours ago, iceman06 said:

To respond to your previous post, my D disk is completely empty, I only store old secondary games on it.

Yes apologies, I meant your C drive, especially if your pagefile is on it. 

[iceman06]

1 hour ago, BIGNEWY said:

Yes apologies, I meant your C drive, especially if your pagefile is on it. 

Indeed, pagefile is on Disk C, it was configured at 32GB when my Dxdiag was sent, unfortunately the games weigh so much now I had not foreseen this eventuality 5 years ago. Only DCS, Rdr2 and GTA 5 are present on this disk, however I do not think that my capacity is guilty of these stutters because my other modules work fine.(I also had these problems before adding the Nevada maps which weighs a little over 30GB)

One thing I noticed when watching the tracks is that it doesn't reproduce the stutters as they actually were during live gameplay. You really have to play to see their intensity on the performance analyzer.

It remains to be seen for my part the Nvidia driver, I will also get the RTX3080 from my girlfriend's PC for a test

[iceman06]

@BIGNEWY 

Hello!

after a test I come back to inform you that changing the graphics card and drivers did not change the problem.
Another idea that comes to mind is to activate ResizeBaR however I have to upgrade my bios to a more recent version to have access to it. Has anyone been able to reproduce the problem with the viper and the same map?

[darkman222]

@iceman06I just tried your track file in 2d without any issues. I also tried it in VR which immidiately shows if something tanks performance. But even in VR its a smooth ride. See my CPU frame time graph from fpsVR.

Only minimal CPU frame time spikes. Which wont cause any issue. I would not see any relation to the F16 radar altimeter. Must be a coincidence.

 

Coming from an Intel switching to AMD I must say that Intel processors have a vey small L3 cache compared to AMD. I switched to AMD a week ago and the CPU frame time is now half compared to with the Intel.

Dont take it personal but a 5 year old PC in the configuration you are using is not considered top tier for DCS.

 

You can eliminate the radar altimeter causing issues with the same test on the caucasus map on the borders of the modelled area, where there is not much geometry to render. In your track file I would suspect the airfield, houses etc geometry being loaded and unloaded to cause the stutters.

Probably use the DCS low graphics preset and replay your track file with that and see how it performs. That way you can reduce the workload of geometry and textures being loaded and unloaded as possible cause of the sutters.

Edited May 16 by darkman222

[BIGNEWY]

14 hours ago, iceman06 said:

@BIGNEWY 

Hello!

after a test I come back to inform you that changing the graphics card and drivers did not change the problem.
Another idea that comes to mind is to activate ResizeBaR however I have to upgrade my bios to a more recent version to have access to it. Has anyone been able to reproduce the problem with the viper and the same map?

Let me know if the bios update helps. 

We have not been able to reproduce the problem our end unfortunately. 

[iceman06]

2 hours ago, darkman222 said:

ziceman06Je viens d'essayer votre dossier en 2d sans aucun problème. Je l'ai aussi essayé en réalité virtuelle qui montre inhumyablement si quelque chose se met en performance. Mais même en réalité virtuelle, c'est une bonne conduite. Voir mon graphique de temps de la CPU de fpsVR.

Seules des pics de temps de délai de CPU minimaux. Ce qui ne causera aucun problème. Je ne verrais aucune relation avec l'altimètre radar F16. Cela doit être un hasard.

 

Venant d'un passage d'Intel à AMD Je dois dire que les processeurs Intel ont un petit cache L3 par rapport à l'AMD. Je suis passé à AMD il y a une semaine et le temps de la CPU est maintenant de moitié comparé à l'Intel.

Ne prenez-le pas personnellement mais un PC de 5 ans dans la configuration que vous utilisez n'est pas considéré comme le top level pour DCS.

 

Vous pouvez éliminer l'altimètre radar provoquant des problèmes avec le même test sur la carte du caucasus sur les bords de la zone modélisée, où il n'y a pas beaucoup de géométrie à rendre. Dans votre dossier de voie, je soupçonne l'aérodrome, les maisons, etc., de la géométrie en cours de chargement et de déchargement pour provoquer les bégaiements.

Probablement utiliser le format DCS bas graphiques et relecture votre fichier de piste avec cela et voir comment il fonctionne. De cette façon, vous pouvez réduire la charge de travail de la géométrie et des textures en cours de chargement et de déchargement comme cause possible des morsures.

When I play the track the stutters do not appear as they actually were during in-game execution, the track is therefore not very representative for analyzing my problem. 

With amazement,I even wanted to replay a track of a fight and saw that an AI enemy dodged my missile and shot me down even though in the game it was me who had shot it down...quite surprising, huh?

I am aware that my PC is getting old and that this is an important factor on this simulator but it runs with a decent fps (80-150 fps 1440p with Dlss) plus,I had no problem with the Hornet and the other modules that I own give me perfectly smooth gameplay.. 

The F-16 seems to pose more of a problem to me for some reason and I can easily say that deactivating the radar alt prevents its jerks from occurring during a roll, I can't explain it,
I've been testing this for weeks and reproduce this every time. The point where you are right is that it is triggered more easily in certain areas such as near Sharjah airport on the golf map. I can reproduce it even in the middle of the desert but indeed this area is more sensitive.

 

 

Edited May 16 by iceman06

[iceman06]

@BIGNEWY Will keep you informed when this is done. Do you know if Resize Bar is supported by DCS just by enabling it in bios?

[BIGNEWY]

As far as I am aware Resize Bar is not supported in DCS currently. 

[iceman06]

@BIGNEWY

Hello, I'm back here to give a little feedback following other tests that I was able to do and which unfortunately didn't change anything.

-Started by uninstalling DCS and GTA V then also freed up space (almost 500GB) Clean reinstallation of DCS with only the initial maps and the Persian Gulf.

-Lowered the resolution and all the graphics settings to the point where DCS looked more like the original Combat Flight Simulator than DCS,

I could even exceed my monitor's refresh rate of 240hz without any problem!
With all this, I was still able to reproduce the big Stutters induced by barrel rolls with the radar altimeter activated,

I am formal and those who will say that this is a coincidence are wrong, unfortunately I seem to be the only one to suffer from this on my viper..?
What seems strange is that the Mariana Islands map seems to be less affected or at least not in the same way while it is harder for my fps 

I haven't updated the bios yet so I can still try to activate ResizeBar in case of doubt but with little hope.(I had issues few year ago when upgrading 
to a most recent version so I still want to make sure that this won't be the case before try again)

The thing that would come to mind is perhaps that my configuration does not support the information upload speed introduced by
the radar altimeter which fluctuates much more compared to the barometric altimeterbut as I repeat it is not a coincidence or random because I can 
reproduce it and stop it by activating or deactivating this function. 

 

 

 

 

Edited Friday at 01:18 PM by iceman06

[BIGNEWY]

HI iceman, thank you for the reply and update on your findings. 

I know it can be frustrating when an issue seems to be an isolated one, often it can be the most obscure thing causing problems and they can be difficult to pin down.

I will ask other team members to take another look here.

thank you