< My idea was either an 8088 or an 8086 with a 16-bit AT-style bus. (keep < mind that it's a theoretical idea, and not an actual project -- yet) The 8086 can be used onthe 16bit ISA bus, its a 16 bit cpu with a 16bit bus and 20 address lines. That will do. < -Would it be possible to have CPU cache with an 8088 or 8086? Not needed as the fastest 8086(V30) is 12mhz (there may be faster) and most moden Dram can keep up with that making cache unnecessary. Cache is a was to make a fast ram keep up with a really fast cpu. < - I'd use the 8 MHz 8086 or 8088. Why not the 12mhz parts. Also the 8086 has a small performance advantage. < If this would work at all, what performance would come out of it? Would < perform like an XT, a 286, a TRS-80, or what? It would be a turboXT. IT's been done, check on the design of the IBM PS2/25 or 30. PS2/m30 was a 8086/8mhz, used 30 pin simms, it was ISA8bit (the performance difference was small there). Two cpus require far more complex software and operating system to have any value and the improvement will not be 2x, more like 20%, though multitasking may bo slightly better. < My final question is another slight disagreement with my friend. He sa < that it would be possible to piggyback (like IBM did with the early AT R < chips) a second 8-MHz 8088 onto the existing 8088 in an XT to make it 1 < MHz. I told him that I didn't think it would work. Your right. It would likely not work at all as both cpus are not guarenteed to be in sync and if one gets out of sync they will crash each other. < What exactly would happen if this was done? Would it run at 8 MHz? Wou < it run at 16 MHz, or something in-between? Would it speed up, slow down < melt down, or just fry everything? Crash. Allison