If your console is part of the New 3DS family, you can enable CPU overclock with Luma3DS.
It works as with NTR CFW, and boosts the clock of the CPU to "New" (804Mhz I pressume) parameters for all games, or it can activate more cache memory for the the CPU... or even both at the same time. The issue is, some games crash with this options, and it doesn't make a huge difference at the end with most games.