Question Ray Tracing - is it only GPU-intensive or also the CPU ?

[RagnaSE]

Probably a stupid question. But - ray tracing (Nvidia) .. is it all done on the GPU or does it also make the CPU work harder ?

 

[rgd1101]

nvidia ray tracing is done on the gpu

 

[falcon291]

GPU. Any CPU are too slow for ray-tracing.

 

[TechyInAZ]

So, that's a yes and no answer.

The GPU does all the visual RT effects, but the CPU is also required to do more backend stuff, like processing objects and geometry in the reflections and stuff like that.

As a result, RT is generally both CPU and GPU intensive at the same time. Spider Man Remastered is a good example, the CPU demands go up a lot when RT is enabled and you have the distance of RT objects set at the normal setting or maxed out.

 

[RagnaSE]

I am asking because i have very conflicting results in the games i have played.

In Cyberpunk, i can run RT at max settings and psycho (so, everything maxed) - also DLSS and frame generation ... at roughly 100 FPS
In Control, i can turn everything on max with RT and get around 90-100 FPS i think
In Forza Horizon i can do RT and max settings and get around 80 or so? or maybe more .. its fluid...

The outlayer is Mechwarrior 5 Mercenaries. For one, i can hardly spot a difference to non RT .. but i run the game at max settings without RT .. at 165 FPS or more (165 is what the monitor can do) .. but once i enable RT .. i drop down to 15-17 FPS .. which really is a HUGE drop
(edit: forgot to write .. i did enable DLSS on Balanced as well as Quality in MW5 .. both show the same abysmal result. .. and i feel like the performance with the 4090 there is comparably poor as with the 2070 i had briefly before (not my GPU, just a test GPU))


I only have a 3700x CPU though .. so i thought, - maybe my CPU is bottle necking it

So tltr. - my GPU does great in pretty much every game ... with a tons of FPS .. except for MW5 ..

Or maybe Mechwarrior 5 is just poorly optimized for ray tracing. Like i said - hardly a difference visually ... but a huge drop in FPS.

 

[TechyInAZ]

Those metrics in MW5 sound like a bug honestly. That shouldn't be normal. Unless you have a AMD GPU or a non-RT accelerated GPU.

A 3700X is fine for RT games today, not the best, but its certainly more than capable of play RT games.

 

[RagnaSE]

Just to update the situation .. today Nvidia offered a new driver version 528.49 .. and the FPS in the game have dramatically increased from the aforementioned 17 to roughly 50 FPS. While still far away from what i would expect a GPU like that to act like - it is still a 250% increase or so? (that looks better than saying its still below 60 FPS)

As for the CPU. We ran HWMonitor alongside (just plugged in a 2nd monitor and let it run there) - and it showed that the CPU is almost entirely dormant (hovers around zero to 10% on most cores) - with the occasional core spiking 60 or even 100% - but a constant 80-100% on Core 1. So maybe the game is just optimized in a way to bottleneck on a single core .. which i find a bit odd in a time when there are no single cores around at all anymore.