VR Performance on a 3080

[TMW89]

Hi,

so i purchased a copy of GTR 2 on steam.

Installed crew chief for the vr and its running.

Its running really poorly however.

I'm using a Hp Reverb G2 on a 3080 and 8700k oc to 4.8ghz, 16gb dd4 - should be a decent rig

I'm barely getting 45fps at spa in the rain with 61 cars at 100% steam resolution. surely this isn't normal?

I've tried changing the in game settings down from high to medium and still the same.

Anyone got an idea?

 

[Jempy]

Don't forget that at the start GTR2 was done using 2GB RAM on single threaded CPU .... and you're asking here surely the maximum: rain and full grid with so many cars ( hoping it's not the night also and with original cars and not a heavy modern mod )

I don't remember if CrewChief brings 4GB Patch above but sure for the CPU affinity.

With the same weather and so many cars and using CrewChief + 4GB Patch + affinity on different cores ..... I get nearly the same situation with a single screen 34" 3440*1440 at rainy Spa on the grid. ( much better after a full lap as less cars are visible ) and my PC is I7-9700k - RTX 2070 Super Trio 8GB - Ram 16GB also.

If you can limit the visible cars this might surely make the situation better but not fully perfect on grid and in the first turns at Spa with 60 original cars.

 

[The Iron Wolf]

Don't forget that at the start GTR2 was done using 2GB RAM on single threaded CPU .... and you're asking here surely the maximum: rain and full grid with so many cars ( hoping it's not the night also and with original cars and not a heavy modern mod )

I don't remember if CrewChief brings 4GB Patch above but sure for the CPU affinity.

With the same weather and so many cars and using CrewChief + 4GB Patch + affinity on different cores ..... I get nearly the same situation with a single screen 34" 3440*1440 at rainy Spa on the grid. ( much better after a full lap as less cars are visible ) and my PC is I7-9700k - RTX 2070 Super Trio 8GB - Ram 16GB also.

If you can limit the visible cars this might surely make the situation better but not fully perfect on grid and in the first turns at Spa with 60 original cars.

You are correct - rain is very heavy on the CPU, and double so in VR. Unfortunately, 4Gb cannot be done without an external app. I am thinking about adding a check to the CC app that checks if GTR2.exe is 4Gb patched, maybe one day.

However, plugin offers multiple performance settings and also includes memory usage optimizations, they might help somewhat. But all in all, rain, shadows, headlights and situations with many cars in a pileup can run GTR2 into ground.

 

[TMW89]

im tried running 30 cars at night no rain, performance tanks. cpu usage is 13%. cpu usage is low too and so are the gpu frame times. like 1.2 however its a stuttery mess. exe has been patched and followed all the settings. surely something is a miss.

 

[RasmusP]

im tried running 30 cars at night no rain, performance tanks. cpu usage is 13%. cpu usage is low too and so are the gpu frame times. like 1.2 however its a stuttery mess. exe has been patched and followed all the settings. surely something is a miss.

What you're missing is that your CPU has 6 Cores / 12 Threads but GTR2 can't use them.
What you're seeing in TaskManager etc. is the AVERAGE usage of the cores between a refresh cycle of the monitoring tool.
In reality though, a CPU core can only "DO" or "PAUSE" and GTR2 can only use 1-2 cores/threads.
At 4.8 GHz that's 4.800.000.000 CPU cycles per second averaged when you have TaskManager at the standard refresh tick.

The Windows scheduler shuffles the load around across more than 2 cores since it's more efficient in most situations. If you don't lock your CPU to the same clock speed on all cores, you would probably see the first CPU core being used up to 100%.
On AMD Ryzen CPUs you usually lose performance when manually overclocking all cores to the same clock speed and it's better to leave it alone, doing its thing with the cores boosting independently.
That's why you usually see 1-2 cores fully loaded on AMD system but not on manually OC'ed Intels.

To give a basic calculation of what overall CPU load to expect from a 1-2 cores game:
100% divided by the number of virtual threads (12 in your case) x 1.5 = (100%/12)*1.5 = 8.33% * 1.5 = ~13%, which is exactly what you're seeing.

Sadly almost all simracing titles can't use the amount of cores modern CPUs offer. It's pretty difficult to split a chained physics calculation to run in parallel. You can't calculate the aerodynamic before knowing the ride height. So you have to start each physics engine tick with the current speed, driver inputs and the contact points of the tyres with the surface.
Then calculate the whole car from there.

Big developer teams can achieve better CPU usage but smaller teams or teams without enough spare money can't. Sadly.

 

[TMW89]

so would i see any benefit to locking the application to just two cores?

what does everyone else do, not use the rain at all?

 

[RasmusP]

so would i see any benefit to locking the application to just two cores?

what does everyone else do, not use the rain at all?

Sadly you can't do anything at all..
The only thing that would actually increase your fps would be to un-sync your cores and test if you can get 5 GHz on 1-2 cores with the other cores clocked a bit lower.
Or you could disable Hyperthreading, disable 2-3 cores and try to boost the active 3-4 cores higher. Or 2 of them higher, the other 2 a bit lower.

But yeah, everyone else apparently patches the game as much as possible (I'm not into GTR2, my information was generic for all simracing titles) and adjust the event settings and/or graphic settings.
Sadly not much you can do apart from buying a 12600k/5600x/5800X3D

 

[Shovas]

Some time ago, I used Task Manager CPU performance graphs to deduce that where GTR2 uses threads they get distributed evenly across all cores. So, enabling all cores is always helpful. It's just how much more helpful they are is questionable.

The problem is GTR2 is mostly single-thread and so it's mostly one CPU that gets slammed.

That said, allowing GTR2 to use all cores via Process Lasso or Bill's Process Manager or Crew Chief is a significant win and you should always do it. I'd say 50-100% improvement.

 

[Shovas]

You mentioned low CPU usage but poor graphics fluidity. Is there a hardware bottleneck or is it all GTR2?

I know on my i7 2600k @4.2Ghz I could bottleneck the main core with GTR2.

 

[TMW89]

the cpu usage isnt particularly high ever or the cpu times. im gonna try a fresh install and see what happens.