As far as I'm concerned there is only one model of the Intel 8089 (the D8089A-3). I am not able to find any information on this. While the 8086,8088 and 8087 use the scheme of the last number (-3 in this case) being -2 on 8MHz versions and (seemingly very rare) -1 for 10MHz versions, the -3 for me seems out of place.
Also what clock is it using? I found info about it being 5MHz or 6MHz. But didn't find any 8088 CPU (for example) that used 6MHz.
So is the 8089 just so rare that only this version exists, and where can you find info on different versions? Where there 8MHz versions that would work with the 8088-2 or the 8086-2?
One theory that I have is that this processor simply is capable of running on all clock speeds mentioned here.
Sorry for my English and thanks in advance. I'm asking this cause we're maybe going to build an IAPX-88/21 system on breadboard. (as in the IAPX-88 manual there isn't much info on building a system only with the 8088 and 8087)