Today I saw that the Intel APX-188/186 User's Manual states that you can use a 8087 as coprocessor for the 80188/186 (as the 80187 is only usable with the 186). But I was wondering about the clock frequency. In the figure on page 255 it can be clearly seen that it ran at 6 MHz. And while that's the native clock of the 80188, the 8087 runs at 4 MHz by default and no revision was written. So while I would expect (for example) an Intel N80188-10 and an Intel D8087-1 to run together (both have a 10 MHz clock), I would never use chips with different clocks.
So to the question:
Is Intel there just expecting you to use the correct revisions (I doubt that because, to my knowledge, there was never a 6 MHz version of the 8087)? Or is Intel "overclocking" a 8087 here?
Maybe does the 8087 in fact support that clock and it has never been told?