I thought I’d lost this, but found it in a storage crate with my A500 and rather more floppies than I would have expected. It’s a Microbotics M1230XA 50MHz CPU upgrade, with a pre-production 68030 that’s not marked as such, and also with a 40 MHz 68882 FPU.
It has a DIMM socket on the back and is fitted with a DIMM. 12 chips - 4 x 1Mbit and 8 x 4Mbit which must mean byte parity is in play.
I bought it secondhand from a colleague and almost instantly regretted paying whatever it was he’d asked for. I did get a little use out of it - if I bought it in '94 then it was about a year before I took the plunge to Pentium.
If I find the A1200 I’ll fit it back in where it belongs.