I’m sure you did not understand me, but I’ll explain. On the territory of Russia and CIS countries was not licensed products of Nintendo in the 90th years. Therefore, almost all played at Dendy, ie clone console Famicom. This console is different from the original. Look here - wiki.nesdev.com/w/index.php/Clock_rate.
Interestingly enough, this mode exists in Nestopia. But I can not enable it in any way, besides I’m interested in the implementation of the console emulation in FCEUMM.