[SOLVED Kind-of] Random framerate drops in missions linked with drops in processor usage.

[Sérvalpilot]

I've been having this issue for a while and I finally decided to report it after reinstalling DCS didn't work.

In desktop mode, I get a fairly consistent 60 frames per second with similar CPU and GPU usage on busier missions. Sometimes my framerate drops to between 5 and 8 for a few seconds and my processors' usage drops as well (see the image below).

It goes back to normal after a few seconds.

I tried to pin down what causes this painful slowdown, but no luck. Verifying file integrity, disabling all mods, and reinstalling DCS doesn't work. Log files don't seem to show anything unusual either.

Edit: Turns out DCS makes my CPU heat up to the point where thermal throttling kicks in.

Edited January 3, 2022 by Sérvalpilot
Fixed a typo

[TAW_Impalor]

PC specs, game settings? My money is on textures loading from HDD as you progress down the map.

[Sérvalpilot]

21 hours ago, impalor said:

PC specs, game settings? My money is on textures loading from HDD as you progress down the map.

I have DCS on a solid-state drive.

I don't think specs are the problem unless it's a driver problem, but here you go:

CPU - AMD Ryzen 7 3750H
GPU - NVIDIA GeForce GTX 1660 Ti
16 GB RAM
500 GB SDD (where I have DCS installed)
1 TB HDD

Here's my settings:

[TAW_Impalor]

2 hours ago, Sérvalpilot said:

I have DCS on a solid-state drive.

I don't think specs are the problem unless it's a driver problem, but here you go:

CPU - AMD Ryzen 7 3750H
GPU - NVIDIA GeForce GTX 1660 Ti
16 GB RAM
500 GB SDD (where I have DCS installed)
1 TB HDD

Here's my settings:

Is your page file on SSD? 16gb may be a problem. Check in Resource Monitor - Memory - Hard Faults. Keep it open and check if the number goes up when you have stutters. Means your pagefile is acessed. Unless it is on NVMe drive, you may need to buy more RAM.

[Sérvalpilot]

@impalor I don't think I had this problem before 2.7 so I don't think it's a hardware issue.

I took your advice and checked the resource monitor for any changes during these spikes. Memory hard faults don't seem to change when they happen.

However, I found this:
 

 

What does the blue line represent?

Edited December 9, 2021 by Sérvalpilot

[TAW_Impalor]

From Google: The blue line shows the total processing power (CPU frequency) available to the system. 

Check with HWInfo if your core frequencies are dipping, and why. Maybe they throttle due to temperature or hit power limit. If you are on a laptop termal throttling is very likely! 

Edited December 9, 2021 by impalor

[Sérvalpilot]

@impalor Thanks for the help!

I found the problem, it is indeed thermal trottling. When my CPU gets above 100 I get the framerate drops.

I wonder why it's happening just with DCS though.

[TAW_Impalor]

Compared to your other games? DCS must be utilizing more CPU and GPU. First step, you may try cleaning the vents.

[Sérvalpilot]

It doesn't happen with other games and programs where my CPU usage gets closer to 100%.

This is quite a weird problem. It may take me a while to figure out how to fix it.

[TAW_Impalor]

2 hours ago, Sérvalpilot said:

It doesn't happen with other games and programs where my CPU usage gets closer to 100%.

This is quite a weird problem. It may take me a while to figure out how to fix it.

Probably your CPU and GPU are sharing the same cooling infrastructure. DCS loads GPUs to the limit. See how you can help your laptop dispose of the heat.

[Sérvalpilot]

I think I figured it out.

It seems like DCS, for whatever reason, uses the integrated Ryzen Vega GPU quite a bit. 
Turning down the maximum Vega iGPU clock frequency and CPU TDP helps quite a bit. Now my CPU rarely goes above 95 degrees even on busier missions.