Some CPU BIOS settings are pretty bad for DCS VR...

[RealDCSpilot]

I only stumbled over this because my mainboard was finally getting a BIOS with ReBAR feature. So i had to flash the new BIOS and go through all my almost 2 year old OC (4.8GHz) and mainboard settings again. For some reason i forgot to disable certain features and my DCS VR performance had changed from extremely good to crappy as hell. First i thought ReBAR was the culprit, but then i found that i didn't change some important settings.
I was always wondering why some people, especially with equal hardware to mine, were having a stuttering experience while i had a blast on my end with very high to extreme graphics settings, especially in massive MP missions in Syria.
TLDR: disable any so called "enhancement" and power saving features of your CPU and, the old news, if you OC - try to get as near as 5 GHz as possible, at least with 4 cores (and set affinity for the DCS.exe).
DCS needs as much as raw power as possible, we all know that. So if you have a pretty decent gaming rig and performance issues, look for CPU settings like "Enhance Multi-Core Performance", "Intel Turbo Boost Technology" and everything else that might be related to power saving instead of lifting the limits. Yes, these features are actually power saving mechanics, they limit and restrict. If you don't need hyperthreading, disable it too. These features are meant for different scenarios than gaming, a game is a very dynamic scenario with lots of sudden changes in core usage, in DCS's case on a maximum of 4 cores for instance. It's the opposite of a 3D rendering scenario, where every core is basically running under the same conditions. In my case i forgot to disable Intel Turbo Boost and my CPU performance was crippled. I couldn't detect it first, because frametimes and FPS values looked ok, but inside the headset i had stuttering and motion smoothing was going crazy most of the time. What i assume is that Turbo Boost was way to slow to react to DCS's per core fast switching thread demands. It tried to chase core usage and readjust, but always to late and missed the perfect clockspeed anyway.
On my end, everything is working well again. Every component, RAM, SSD and GPU, runs perfectly optimized with highest possible bandwidth through the CPU.

Edited May 18, 2021 by RealDCSpilot

[Hoirtel]

18 minutes ago, RealDCSpilot said:

I only stumbled over this because my mainboard was finally getting a BIOS with ReBAR feature. So i had to flash the new BIOS and go through all my almost 2 year old OC (4.8GHz) and mainboard settings again. For some reason i forgot to disable certain features and my DCS VR performance had changed from extremely good to crappy as hell. First i thought ReBAR was the culprit, but then i found that i didn't change some important settings.
I was always wondering why some people, especially with equal hardware to mine, were having a stuttering experience while i had a blast on my end with very high to extreme graphics settings, especially in massive MP missions in Syria.
TLDR: disable any so called "enhancement" and power saving feature of your CPU and, the old news, if you OC - try to get as near as 5 GHz as possible, at least with 4 cores (and set affinity for the DCS.exe).
DCS needs as much as raw power as possible, we all know that. So if you have a pretty decent gaming rig and performance issues, look for CPU settings like "Enhance Multi-Core Performance", "Intel Turbo Boost Technology" and everything else that might be related to power saving instead of lifting the limits. Yes, these features are actually power saving mechanics, they limit and restrict. If you don't need hyperthreading, disable it too. These features are meant for different scenarios than gaming, a game is a very dynamic scenario with lots of sudden changes in core usage, in DCS's case on a maximum of 4 cores for instance. It's the opposite of a 3D rendering scenario, where every core is basically running under the same conditions. In my case i forgot to disable Intel Turbo Boost and my CPU performance was crippled. I couldn't detect it first, because frametimes and FPS values looked ok, but inside the headset i had stuttering and motion smoothing was going crazy most of the time. What i assume is that Turbo Boost was way to slow to react to DCS's per core fast switching thread demands. It tried to chase core usage and readjust, but always to late and missed the perfect clockspeed anyway.
On my end, everything is working well again. Every component, RAM, SSD and GPU, runs perfectly optimized with highest possible bandwidth through the CPU.

Matches my experience. I overclocked my i9 9900 to a cool and stable 5.2 with HT off and disabled enhancements. I also have this with no AVX offset too. My CPU scores a little better on single thread scores, worse on multicore benches - but its tuned for my uses. 

[FoxTwo]

Multi core enhancement or Enhanced Turbo (MSI) sacrifices single core boost performance for higher overall multi core performance. It's not about power savings, it's the opposite. It's a form of factory overclocking but will only benefit applications that specifically utilize multiple cores, which DCS currently does not.

[Hoirtel]

6 minutes ago, FoxTwo said:

Multi core enhancement or Enhanced Turbo (MSI) sacrifices single core boost performance for higher overall multi core performance. It's not about power savings, it's the opposite. It's a form of factory overclocking but will only benefit applications that specifically utilize multiple cores, which DCS currently does not.

Interesting.. I'm definitely no expert.. I had thought that MCE was an all core boost that would keep all cores and threads at the highest single core clocks possible (to boost value) regardless of power saving limits, until it gets too hot. This should give highest possible single and multicore performance. You are saying that it reduces single performance for the greater benefit? By reducing clocks? Like I said I'm no expert so happy to learn if I had the wrong idea.

Edited May 18, 2021 by Hoirtel

[RealDCSpilot]

8 minutes ago, FoxTwo said:

It's a form of factory overclocking but will only benefit applications that specifically utilize multiple cores, which DCS currently does not.

Yep, and it will never work like these applications with equal jobs that can easy run paralleled and synched, because it has very different jobs to run on each core. 

Edited May 18, 2021 by RealDCSpilot

[RealDCSpilot]

@Hoirtel Look at it this way, if you have ten cores and give each core the same equation to solve, they will run perfectly parallel and can easily be synchronized. If MCE detects such a task, it priorizes it against all other single threaded tasks. A game can never work like this, so MCE doesn't engage.

Edited May 18, 2021 by RealDCSpilot

[FoxTwo]

11 minutes ago, Hoirtel said:

Interesting.. I'm definitely no expert.. I had thought that MCE was an all core boost that would keep all cores and threads at the highest single core clocks possible (to boost value) regardless of power saving limits, until it gets too hot. This should give highest possible single and multicore performance. You are saying that it reduces single performance for the greater benefit? By reducing clocks? Like I said I'm no expert so happy to learn if I had the wrong idea.

 

 

It depends on the CPU.

 

On the 10 and 11 series intels, MCE will take power/heat budget away from the single core boost in order to guarantee the higher overall multi core boost.

 

On the 8 and 9 series it was a performance adder with no real downside.

[Hoirtel]

2 minutes ago, FoxTwo said:

 

It depends on the CPU.

 

On the 10 and 11 series intels, MCE will take power/heat budget away from the single core boost in order to guarantee the higher overall multi core boost.

 

On the 8 and 9 series it was a performance adder with no real downside.

Ah yeah. Makes total sense. My experience is bias to my 9th gen. But yes the 10 and 11 have that 5.3 single core super dooper turbo. Always thought that was a bit of a gimmick to be honest....

[RealDCSpilot]

It's pretty awesome how much modern CPU's are customizable for very different scenarios and tasks. In DCS's case, stock settings definitely aren't the best starting point to just go and lift off in VR and hope for the best.

[Hartsblade]

Is this just an Intel based phenomenon, or are there AMD equivalents?

[RealDCSpilot]

I think it affects all processors in some way, it depends on what auto/standard settings mainboard manufacturers provide in their BIOS.
In my testing sessions i found that these options worked against DCS's VR performance (high end system on extreme image quality settings).
My recommendations besides classic OC:
- Intel Turbo Boost Max Technology (i set it to Legacy)

- Hyper Threading Technology (disabled)

- Intel Speed Shift Technology (disabled)

- CPU EIST function (disabled)
- Enhanced Multicore Performance (disabled)

- Intel Turbo Boost Technology (disabled)

 

Edited May 20, 2021 by RealDCSpilot

[winghunter]

Anyone knows what to do with those other settings ? I just disabled Hyperthreading it was causing my core utilisation to go down due to DCS single thread.

Edited January 6, 2023 by winghunter

[Paul_Exotic]

On 5/18/2021 at 11:01 AM, Hartsblade said:

Is this just an Intel based phenomenon, or are there AMD equivalents?

Off hand I know there were some Ryzen specific settings.  Can't check mine until I get home from work but I know one big one was SMT or Simultaneous Multithreading 

5 hours ago, winghunter said:

Anyone knows what to do with those other settings ? I just disabled Hyperthreading it was causing my core utilisation to go down due to DCS single thread.

 

Also want to disable Intel Virtualization Technology unless you need to work with Virtual machines with things like VMWare, Hyper-V or VirtualBox

[oldcrusty]

When I recently got my 13900k with 64gb of DDR5 and finally went back to win11 (with latest updates), someone suggested to give it a shot and leave the bios alone and setup the power management in windows and forget OC'ing... let the damn thing manage clocks and voltages on its own.  Yea right...  It was worth a try though.

In bios, I only did couple of minor changes, disabled HT and reluctantly left all the C-states enabled (including C7... whatever the heck that does).  I left the virtualization enabled. In windows, I selected balanced power scheme and modified it a bit, stuff like USB, WIFI, etc.  For CPU, I set the limits between 30 and 100%  Also, just to see if it makes any difference, I left the memory integrity feature enabled in windows security.  It didn't make any difference in performance on my rig. (the recommendation for gaming is to disable it) 

It's humming along!  When I run DCS, the clock is at 5.5 GHz without a hiccup (it starts at 5.8 then for some reason settles at 5.5) The temps are around 50, 55'C.  I might try to OC later on. It should be easy to bring it up to 6.2 or so.  Pcores, Ecores... , affinities and so on... I'm not going to mess with that.   This CPU is a totally different game.

 

[winghunter]

I can reach 70 fps now with my 3ß70 while with hyperthreading i couldnt due to cpu limit. Also there seem to be less of the DCS stutters. Im on windows 10 though and DCS 2.7

[Steel Jaw]

Are we saying that turbo boost should be disabled?

[Paul_Exotic]

7 hours ago, Steel Jaw said:

Are we saying that turbo boost should be disabled?

Yes