arnold render CPU and GPU's quality is different?

[tom3401]

Hello. I recently find out that GPU rendering is way faster that using CPU.

However, when I compared both pictures rendered by CPU and GPU, this happened.

CPU rendered

GPU rendered

I thought both rendering works exactly the same, except using different calculation. 

Should I try more denoising process? Or is my graphic broken?

I wish to know.

p.s. I'm using geforce RTX 2070 super

[Stephen.Blair]

The sampling is different on GPU. There's no splitting, so you need higher AA

https://docs.arnoldrenderer.com/x/i4QsBQ

Matching Noise on CPU and GPU

Matching noise can take a little experimentation because Arnold GPU uses Camera (AA) sampling only. We recommend you also use Adaptive sampling. Here are some guidelines:

• Set the Max. Camera (AA) in the range of 30 to 50 (depending on the scene, you might go closer to 100). In general, the max samples should be a large value. A large max samples means that the quality is controlled by the noise falling under the threshold, instead of by clamping to the max AA.
• Set the Adaptive Threshold to something like 0.015 or 0.02. For a noise-free render, lower the threshold value, maybe even as far as 0.010.
• Set the Camera (AA) samples to around 3 or 4. One of the few reasons to go higher with AA is for motion blur. The higher the number of Camera (AA) samples, the less of a speedup you'll get from adaptive sampling.

[tom3401]

I tried maximum scale of both camera AA and max.AA

.....and it still has so many grains.....

Should I try something on actual cameras?

Is there any arnold control setup to remove grains in camera attribute editor?

I really wonder.

*due to uncertain process, I'm rendering my image as JPEG sequence.

[kenne150]

I was wondering if you found a fix for this? I was hoping that GPU rendering was a good update, but from what I've encountered, it's trash. 😕 So much for quicker renders.

[carlos.come]

Did you figure out a solution for this? I'm in the same pickle!

[Christoph_Schaedl]

Use only 4 samples for AA. 

Up the samples in your lights to 2.

Lower the noise treshold.

https://youtube.com/shorts/3_4CpoD9c0o

https://youtu.be/XZfsqJ0_9go