Raceroom cpu or gpu bound

[Des Pearce]

Currently, on similar settings, ACC is running better than Raceroom in AI races. I run a 20 car grid and fps sit between 70 and 90fps on my 100hz monitor, getting it to 100fps seems impossible even when graphics are set fairly low. Gpu load is 60-70% and cpu is 40-60% load.

My setup is i7-9700kf, 16gb 3600mhz ram, 2tb M2 nvme drive and rtx 3080. I assume I'm cpu rather than gpu limited in this case. Is it just a case of smaller grids, would overclocking the cpu help or is there anything else to consider. ACC runs a steady 100fps starting from the back of the grid in clear conditions and shows 60-70% gpu l9ad and 30-40% cpu load.

 

[Emery]

If GPU is not showing 98-100% load, then you're CPU bound.

 

[Des Pearce]

That's what I thought, not tons of room for improvement is there from what I have?

Any ideas of reducing cpu load?

 

[Emery]

Cut the number of cars in half and see how well it responds?

 

[Des Pearce]

 

[Case_]

Unless you see 100% GPU utilization (or very close to 100%), you're pretty much guaranteed to be CPU bound. Not just in Raceroom, but particularly in Raceroom due to it basically running on two threads *and* using DX9, which runs out of breath very easily. Do a race on Spa with a decent amount of say GT3 cars and watch the framerate plummet as you drive down the hill towards Eau Rouge, especially on the first lap with most of the field in view (that's my Raceroom stress test, in fact - haven't found a better/easier way to bring Raceroom to its limits).

And yes, lowering visible cars helps probably the most, at least in my experience. I run around16-20 to keep the framerate above 60 in above mentioned scenario.

 

[Case_]

(I just realized the first sentence really should be "unless you see 100% GPU utilization while you're not using vsync and/or limiting your framerate through other means, you're pretty much guaranteed to be CPU bound". Small difference, but important to point out. I always forget about this because I always assume people talk about framerates only in the context of vsync off and no limiter.)

 

[Des Pearce]

(I just realized the first sentence really should be "unless you see 100% GPU utilization while you're not using vsync and/or limiting your framerate through other means, you're pretty much guaranteed to be CPU bound". Small difference, but important to point out. I always forget about this because I always assume people talk about framerates only in the context of vsync off and no limiter.)

Actually you're right, I do run vsync to limit frames, and gpu usage, to 100fps. I've raced a couple of more times since and not had an issue so not sure what the problem was.

 

[Case_]

(I would advise against using vsync, at least not without other tweaks, since it creates input lag. But some people are not sensitive to it, and I guess at 100 fps, it's also going to be lower than at the "normal" 60.)

 

[Des Pearce]

I notice a lot of tearing when I disable vsync, not sure what else to do. If I get the Reverb G2 running how I like it'll be immaterial anyway

 

[Deleted member 197115]

I notice a lot of tearing when I disable vsync, not sure what else to do. If I get the Reverb G2 running how I like it'll be immaterial anyway

Keep VSync (use Adaptive on non VRR monitors), just set prerendered queue to 1 (Low Latency On in newer NVidia driver).
HMDs are using own hardware sync based on refresh rate, there is one nasty thing about R3E, while most titles ignore in driver VSync settings when in VR mode, R3E honors them, which creates stutter even if monitor refresh rate matches HMD's. Set it to Off.
SMS titles are different though, their mirror screen is rendered separately (not a real VR mirror as it should be), so enabling VSync there will help the performance.

 

[Case_]

The best options to get rid of tearing with low-ish input lag without Freesync/Gsync are either turning vsync off and using the scanline sync feature in RTSS, or keeping vsync on and limiting your framerate to a value of 0.01 fps below your true refresh rate in RTSS again.

Also using true fullscreen, not borderless window (you won't get tearing in borderless window, but you'll likely get intermittent microstutter and permanent high input lag).

Adaptive sync is useless, it behaves like normal vsync when your framerate is the same or higher as your refresh rate, and tears when it is below that. Prerendered frames/low latency only somewhat reduces input lag, but can also cause stuttering if set too low for a given title (the value can vary between individual games).

 

[Deleted member 197115]

Adaptive sync is useless, it behaves like normal vsync when your framerate is the same or higher as your refresh rate, and tears when it is below that.

It is much better experience than jarring drop to half refresh rate with regular VSync. So no, not useless at all.
Most lag people complaining about with VSync comes from that flip queue, Low Latency set to On will keep it at 1, it's good enough for pretty much everything, if you set it to Ultra, that can create some stutter when CPU can't keep up, as there is no flip queue per se, it's actually better for VRR monitors as it sets frame limiter just a bit under refresh rate. I still find it less reliable even with G-Sync enabled monitors than Low Latency On.

 

[Emery]

And there's always Fast Sync in the nVidia control panel.

 

[Case_]

OK.