4 MHz Z80
In that Tatung Einstein (had one as well - CPM compatible).
Where did you get a 5Mhz 8086? I thought the general clock was 8MHz (was in my PC1640 anyway). Your 80386 was underclocked as well (or was that turbo off speed?) - even the SX normally was 20 MHz the DX normally being 33 MHz.....