Bright pixels appear on my model in material preview with Cycles on Blender 2.82 I am currently following Blender Guru's donut tutorial for 2.8, but I've had an issue with the material preview in the viewport. This seems to come from the donut, where the entire object simply pixelates with bright and blinding white pixels along with a few other rainbow colors. When moving my view around, the pixels leave a trail too. I don't know if this is an issue with switching from Eevee then to Cycles, or if it is something else. Here is how my issue looks like:



If I add back the icing and sprinkles:



When I zoom in and out:



Edit: Here are my computer specs:


Name: ALIENWARE13R3
Processor: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60 GHz
RAM: 32 Gb
System: x64
OS: Windows 10
GPU: NVIDIA GeForce GTX 1060


Here is the blender file to download on MediaFire:
Donut Tutorial.blend download
So I opened your file on my machine and have to inform you that the glitches only occur on your end.

The doughnut looks just fine in my Viewport:



And renders beautifully (this render was done with only 8 samples in about 7 seconds):



Since you are using a laptop I suspect the switch between IntelHD-Graphics and your dedicated chip my be the cause of this problem. Since I'm not a Windows user I can only give you limited advice on this issue:


Make sure all your hardware drivers are up to date.
Start Blender with your GTX enabled (right-click on the application, then choose something like "run with NVIDIA")
If that doesn't solve your issues and you're positive that neither your OS nor your hardware are at fault here, try filing a Blender bug-report.