This 25 MHz full-AT 386 mainboard with 8MB onboard DIL-RAM had a strange "speed issue":
At about one out of 5 starts the POST beep had a higher frequency and the CPU finally operated at 8.3 MHz instead of 25 MHz.
The tick-sound during memory count was changing it´s tune during the test - something I have never heard before.
After cleaning all the chipset contacts and resoldering lots of suspect solderings the issue was still there.
Since the chipset is socketed I tried swapping the chips one by one and it turned out the "P82A306A" was the culprit.
I couldn´t find a datasheet, just one reference saying it´s a "control signal buffer"

I wonder if ihis board/chipset would support 16MB RAM if the RAM add-on card (2nd slot from thew top) would be used?