@DDark, "hardware" is more than a CPU. It's also audio and video processors, all sorts of radio chips (BT, WiFi, GSM, GPS, FM...), memory managers, memory chips, memory card readers... Most of these need drivers. And for most of the new ones the drivers are awailable only in a binary form and only for a specific platform. Writing Linux drivers requires a detailed knowledge of the chips' internals - in other words a Technical Reference Manual.

Besides, I do not really know if a newer/faster/beter CPU is really binary compatible with an older version, i.e. would a driver/OS component/application built for the older work without issues on the newer or would it need recompiling first. It was the case the last time I did some hardware work but that was in a different century.