If you want to save a small chassis with a knife card, at least M-ATX will start to get smaller. If you want portability, you should choose itx motherboard. Although the performance of the big board is better than itx, there is little difference for ordinary people ... It can accommodate an ultra-small chassis, a conventional graphics card, a knife card and an itx motherboard ... There are also two models of wind chasers, but the wind chasers are not small enough ... M- Lenovo ThinkCentre chassis counts as one, and most of HTPC Dell are quasi-systems, which is very troublesome to transform ... Of course, Lenovo can directly use it. ....