Just finished installing the 4x overclock mod for the DMG (used a GBC crystal on accident! haha), with an installed switch. The results are....pretty awesome!
The reason that Pokemon messes up so easily, is that the game has a higher power draw than other ones for the system. The switch just isn't perfect with everything, but it works great for regular games like Super Mario Land! This instance though, the 4x crystal oscillator for the GBC really isn't meant for the DMG...but I did it anyways! hah