Request help understanding the In Game FPS counter numbers

[Hoggorm]

Hello,

In VR, when displaying the In Game FPS counter, I see some terms that I would love to know what means:

 

This is using the MT test edition.

 

When FPS is for example reported to be 34:

GPU BOUND (theor. FPS 59.8)

Sorry for the bad picture!

 

Other messages that may appear:

CPU bound (main thread)

CPU bound (rendering thread)

[VirusAM]

In your case it means simply that your GPU is your limiting factor in this scenario.

The problem is that many times you have indicated that the limiting factor is the CPU while it is not true...this happens for example when the FPS are capped for some reason (Vsync, arbitrary user cap, or Motion Reprojection for VR).

[Hoggorm]

Thank you for the quick reply VirusAM

3 minutes ago, VirusAM said:

In your case it means simply that your GPU is your limiting factor in this scenario.

Yes, I understand that my GPU is the limiting factor and that is a good thing I would assume (since it is green an all). But what does (theor. FPS 59.8) mean?

4 minutes ago, VirusAM said:

The problem is that many times you have indicated that the limiting factor is the CPU while it is not true...this happens for example when the FPS are capped for some reason (Vsync, arbitrary user cap, or Motion Reprojection for VR).

I do not follow you here. Is this in relation the the (theor. FPS 59.8) message?

[evanswillo]

Hi,

What are your system specs ?

What Headset are you running ?

 

[Glide]

2 hours ago, Hoggorm said:

But what does (theor. FPS 59.8) mean?

That could be your target FPS (ie. What the headset wants to achieve vs what it is achieving), if you were running your headset at 60hz, like I do with my G2.

Edited March 24, 2023 by Glide

[Hoggorm]

12 minutes ago, evanswillo said:

Hi,

What are your system specs ?

What Headset are you running ?

 

These are my specs:

AMD AM4 Ryzen 7 5800X3D CPU
Kingston FURY Beast DDR4 3600MHz 32GB
MSI GeForce RTX 3090 Ti GAMING X TRIO

I am using the HP Reverb G2 headset.

8 minutes ago, Glide said:

That could be your target FPS (ie. What the headset wants to achieve vs what it is achieving), if you were running your headset at 60hz, like I do with my G2.

 

I believe my HP Reverb G2 VR headset is set to 90Hz. 

In the main menu I have 90 FPS flat, but it seem to be capped at 60 while in game.

VirusAM say that some settings will limit FPS, but as far as I know all these are off on my computer?

 

3 hours ago, VirusAM said:

Vsync, arbitrary user cap, or Motion Reprojection for VR

 

[evanswillo]

Hi I would have thought a 5800x3d paired with a 3090ti would have given better performance.

I run at 90fps in VR using 9900KF and 6900XT.

Are you using OpenXR Toolkit ?

If so what options have you selected ?

 

[Hoggorm]

I must say that the mission I test with is the F-16 Marianas Free Flight Instant mission and I guess it is somewhat FPS heavy. Maybe if you are able to try the same it would be interesting to hear what FPS you get at the start of that mission (overflying the airport).

Yes, I am using OpenXR Toolkit. Unfortunately I am not able to post the settings until late next week as I am currently at work...

 

[evanswillo]

Yes that Free Flight is FPS heavy.

[CptBligh]

7 hours ago, evanswillo said:

Hi I would have thought a 5800x3d paired with a 3090ti would have given better performance.

I run at 90fps in VR using 9900KF and 6900XT.

Are you using OpenXR Toolkit ?

If so what options have you selected ?

 

What settings and scenario are you getting 90fps?

[Lange_666]

17 hours ago, Glide said:

That could be your target FPS (ie. What the headset wants to achieve vs what it is achieving)

That is also there in 2D, i had mine reading 900 !!! constantly in 2D so i let go of my cap and set the maxFPS in the config file to 1000 just to see how far it would go. It jumped around the 200 mark. So that theoretic value is to be taken with a big grain of salt.

[evanswillo]

I use the OpenXR Toolkit to help reduce the stress on the CPU (9900KF)

I will be honest most of my flying is in low-density theaters with very few assets.

 

[Hoggorm]

Thank you for the replies.

I still do not have full understanding of what (theor. FPS 59.8) means in the green  GPU BOUND  message when the actualt FPS appears to be lower.

[Tepnox]

7 hours ago, Hoggorm said:

Thank you for the replies.

I still do not have full understanding of what (theor. FPS 59.8) means in the green  GPU BOUND  message when the actualt FPS appears to be lower.

I think the theor. (theoretical) FPS would be the maximum possible FPS sustained by the CPU in the current scene - makes sense in a way, when the GPU is limiting the FPS (maximum utilization) but the CPU could push out more.

If the CPU would be the limiting factor you can not push more FPS with the GPU, because in this scenario the GPU would always be waiting for the CPU to finish the calculations - here you would have an under-utilization of the GPU (GPU would idle around in parts).

You should always aim for a GPU bound scenario - so the CPU has enough headroom left to always keep up with the GPU.

In a CPU-bound scenario you would also have negative impacts on latency and maybe stuttering issues itself.

[Hoggorm]

Ok, this can make sense. However I am no computer expert at all so I still wonder why this theor. (theoretical) FPS message only appear in the MultiThread test version and not in the regular open beta version?

If FPS is 35 and theor. (theoretical) FPS is the same (35), will that give the same performance, or experience, as FPS 35, theor. (theoretical) FPS 60?

Or will the latter be better?

To me the MT version appear to be more smooth, even though I get the same FPS reported in this specific mission (35 FPS) on both.