You'll need a separate FPU if you want to use it - though in this era it wasn't a standard equipment and in most programs you can get away without it without any performance loss. I think I'd pair a Cyrix FasMath FPU with the DLC, they match and the Cyrix FPU offers good (maybe the best?) performance for this platform. Except for the Intel RapidCAD but that's an entirely different animal 😉

The empty socket must be U32 in the guide, I guess. In the cache SRAM population table you see that it needs a 16kx4 SRAM IC, which is a normal 64 kbit SRAM. It's the tag RAM for the cache so it's definitely needed.

As for RAMs you'll need matching quads of 30-pin SIMMs because they're only 8 bit wide while the 386DX has 32-bit bus. As for the speed rating, well, it should be no more than 70ns. If it's 70 or less ns it's up to luck what kind of timings you can reach with them. So if you want to max out the board you'll need 8 sticks of 4MiB SIMM-30.

MT32 for $32? That was an excellent catch!

Thank you alvaro84. I do enjoy drawing polygon style art in older cad programs (think Sega Virtua stuff) and use older spreadsheets for crazy fish genetic related stuff. I thought something had to go there to activate the cache but was uncertain what. Great answer, and very specific. Now I have to look through all my ram and see what I can find. Looks silly expensive on eBay. $40 - $60 for 8 sticks of 4MB-30pin.

The best part of that MT32 for $32 was that I didn't know they even took that kind of thing. We were trading in kids books and crummy music cd's I got for a dime each at a yard sale (bulk deal b/c stuff I wanted in it) and got it with trade credit. Had been in their display case for a while. I don't usually even go over by the digital camera and musical instruments they have in a display case. This past weekend we got a Joystick / Midi DIN cable that lets you hook both up at the same time for 49¢ half off at Goodwill. That will pair nicely with having it hooked up all the time.