OpenCL has no effect

For the processing that needs PRIME, OpenCL is indeed not used. This doesn’t prevent its use for other processing without PRIME that may happen in the meantime though.

Basically a recent (< 5 years old) discrete GPU is indeed needed to see a benefit with OpenCL. I don’t know about power consumption as it’s hard to get the information, but there’re many great graphics cards below 300W TDP.

Also I can’t tell more for now but please note that for the next version of PhotoLab, having a good GPU will make a significant difference.