Slow physically-Based rendering speed (low GPU usage)

[JBradleyConst]

I feel like the rendering speed of the physically based camera is taking longer than it should (or perhaps could?)

System specs: i7 12700K @3.6GHz, RTX 3080, 64GB RAM

 

When using physically based rendering, it takes quite some time for it to finish rendering.

Samples processed per second when rendering is typically around 20-30 depending on what's in the view.

With the default 2000 sample cap it takes like 1.5 minutes for a view to finish rendering. (rendering window = 1127x857)

However during that time when it's rendering, my GPU usage is only shown to be around 6% to 8% in task manager.

CPU usage is also in the single digits, but I'm thinking that's to be expected since the physically based rendering is GPU based as far as I'm aware.

 

I'm wondering why is the GPU usage so low if the rendering is GPU based?

I feel like if it were using more of the the GPU's power, like 80% instead of just 7%, it would complete the renders much faster?

Also are there any tweaks that may speed things up, either in CA or perhaps settings in the nvidia control panel?

 

 

[SHCanada2]

is this on a laptop? If so, the laptop will typically constrain the GPU when on battery.

 

What version of CA are you using?

[GeneDavis]

I cap my PBR samples at 150 and like the results.  Have you tried something low like this?  My card's a 3070.

[ericepv]

I get a finished PBR in 10-15 seconds with my sample rate at 150-250 (2000 seems awfully high) using a 3060 card.

[SHCanada2]

 

above previous thread has some statistics

 

also depends on X16 vs X15( or earlier) for number of samples