TechSpot posted an investigation into the differences between the 215W desktop RTX 2080 and the 80W mobile Max-Q version.  As you might expect, quite a bit had to be done to drop the power so precipitously including dropping the boost clock to just 1095MHz from 1515 MHz.  To make things even more confusingly there is a 90W variant of the Max-Q which has a base clock of 990 MHz and a boost of 1230 MH and for the most part you will not know which one is installed before you buy the laptop and open it up.

TechSpot offers a look at the performance of the two RTX 2080 Max-Q models here.

"Following our coverage into Nvidia's laptop RTX GPUs, today we're reviewing the top-end RTX 2080 Max-Q. As an "RTX 2080" Turing part, this GPU comes with 2944 CUDA cores, 368 Tensor cores and 46 ray tracing cores. But that's where the similarities between the RTX 2080 Max-Q and the desktop RTX 2080 end."

Here are some more Graphics Card articles from around the web:

Graphics Cards