True Desktop Class Nvidia GTX 10-Series Cards Coming To Notebooks In Few Months (pcgamer.com)
If you're in the market for a new gaming notebook, you might want to consider waiting a few months. PCGamer blog, citing its sources, report that Nvidia plans to release its new 10-series chips for notebooks. From the report: The kick is, they won't be M versions of desktop GPUs. They will be the same chips used on the desktops, just operating at a lower TDP -- we're told there will be the same number of shader units, etc. We're also told that Nvidia will not go back to producing separate M versions of its desktop GPUs, which is good news for those looking for better gaming performance on the road or in a desktop replacement type notebook.
CPUs and GPUs are binned. They test each one which comes out of manufacturing. The ones which by pure luck (fewer impurities, cleaner etchings) can operate at a lower voltage (and thus draw less power) get binned as laptop parts. The rest of them become desktop parts.
It's not like they can manufacture these lower power consumption chips at will. The manufacturing process dictates that by pure change x% will be suitable for laptop use, leaving 100-x% for desktop use.