I was wondering that myself. In my search, I found YouTube videos of Game Corporation and Beta Corporation boards that had the sound at 3MHz (including, in one case, the tempo being too fast as well as the pitch!) but I also found a couple videos of Game and/or Beta bootlegs that ran at the correct 1.5MHz.
Are we sure all Tayto boards used the stock AY-3-8910 instead of the YM2149. And how would that explain how I've found examples of Game Corporation bootleg boards running at each of the two speeds? there could be Tayto boards that run at 1.5MHz as well. Someone would have to hunt down multiple bootleg boards and check them. I'm now wondering if it might have been down to the bootleggers either interchangeably installing YM2149s and AY-3-8910s, or even just neglecting to connect pin 26 on the YM2149. If it's not consistent, maybe it'd have to be implemented as an optional setting in machine config?
Edited by TServo2049 (06/12/17 03:01 PM)