We need to get back to using BTX

BTX doesn't make drastic enough changes, and is still too rooted in outdated conventions. The entire approach to expansion cards needs to change, because we're still using a form factor inherited from the 1980s, just swapping out the card edge connector a few times since then. In the 1980s, expansion cards needed lots of PCB real estate, and systems needed several expansion cards. These days, even GPU PCBs are tiny compared to eg. EISA cards like those [shown on Wikipedia](https://en.wikipedia.org/wiki/Extended_Industry_Standard_Architecture). We need a motherboard layout and expansion card/module design that accommodates today's need for one (1) high-power expansion card (a GPU) to be close to the CPU (so you don't need PCIe redrivers) and to allow good cooling for the GPU that has fans blowing *across* the PCB rather than down onto the PCB. What we're seeing these days with graphics cards is a half-measure; even something like the 5090 FE that gives two fans largely unobstructed airflow through the heatsink with no PCB in the way *still* has the fans blowing in the wrong direction for overall system thermal and acoustic performance. Aside from GPUs, all the expansion cards that a desktop system needs these days fit on M.2 cards (WiFi and SSDs), which have the added benefit of being able to share parts with the much larger laptop market. Workstations could move to the OCP NIC slot for medium-power (25-50W) network and storage needs, to continue sharing parts with servers.