Thanks for the explanation Juraj! That screenshot was taken with HWmonitor after about half hour of rendering with Corona. I tried to do some research on the internet and it seems that many people thinks that HWmonitor might be outdated/buggy and it's recommended to use HWinfo64 instead. So the latter program shows that max difference between CCD0 and CCD1 is about 10 degrees and the average difference is only 3 degrees celsius. Combined that with what you said, i think it looks pretty normal and i shouldn't stress about it too much. Am i right?