The first Pentium processors Intel shipped used a single 5 Volt power supply and came in a “Socket 4” PGA package with a 2.54mm square pin spacing. This means it fits in a protoboard and is compatible with the 5V logic commonly used in homebrew projects.
In a way, the Socket 4 Pentium is the upper limit for homebrew with standard methods. Starting with the Socket 5 revision of the Pentium, the packages had staggered pins and required 3 Volt power supplies. Bus speeds also quickly exceeded what is feasible on a protoboard. Competing processors at the time were already fine-pitch QFP packages and 3V. Anything else of that era or newer will require a custom PCB.
So because it is the apex of protoboard homebrew (as well as completely absurd) here is a Pentium CPU in wirewrap sockets, freerunning at 25MHz.
The CPU is rated for 66MHz, but at that speed draws over 3 Amps of current. If I’ve calculated correctly, that would be enough to exceed the current carrying capacity of the wiring I’ve used.
I just love how ridiculous it looks, taking up most of the board space, and with that heatsink and fan.
Using a Toshiba Libretto 70CT as a DOS gaming console (WASD and the “trackpoint” is a way better setup for Duke3D than the default one - even on this machine)
