What is causing these blocky white spots in the glass lighting? (Principled BSDF)

I am following Blender Guru’s donut tutorial and when I render the glass cup and plate with the Principled BSDF I’m getting blocky white spots. What am I doing wrong?

I’m guessing you either have a bad normal map/wrong settings, or faces aren’t smoothed. If not, please share the project so we can investigate.

Shade smooth was not enabled but that did not fix it. I recalculated the normals but that did not fix it either.

How do we upload projects here?

Use http://pasteall.org if you can’t upload here or file is big.

Here’s the link http://pasteall.org/blend/index.php?id=52904

Weird. I’m not getting those at all. I notice the light source is humongous, and that the bright parts are reflections from that. If you reduce the light source radius from 1.84m, does the size of the squares also reduce, or just which squares the reflection covers?

I can’t test on GPU though. Maybe it is a GPU or other hardware issue? I can’t find anything immediately wrong that would cause anything like that. Pole topo could be improved or at least have flat sections before ending with ngons, smaller light source, more bounces for glass would be desirable (gets rid of that black rim you have), but no real source for problem.

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I reduced the size to 0.1 m and here’s the result.

It appears much better with smaller amounts of the white now. It is strange that the project appeared different on your machine.

Thanks for your suggestion.

Looks much better. You might want to increase the number of glossy and transmissive bounces to get rid of those dark rims.