if you are still into 3DS emulators, you shouldn't relay on DS mode, like elisherer pointed out only 5 cards are capable of emulating GBA games and SNES games propely (there is an SNES emulator for DS, but it's not emulating propely), which is
iPlayer, Supercard DSTwo, which uses the same software,
EX4 DSi, CycloDS iEvolution (which uses DSimode enabled mode to emulate the GBA games on the DSi RAM, which is faster then any memory-on-cart RAM on slot-1 you will ever find, however it's 16MB of RAM, there are 32MB of GBA games which won't fit it, meaning support is limited by HARDWARE) and
iSmart MM, also if you have a DS Lite\Phat you can use an extended RAM to support emulation of SNES games and GBA games with
EZ Flash 3-in-1, it has 16MB of PSRAM(fast, needs electrcity, small amount) and 32MB of NOR FLASH (bigger, doesn't require electrcity, slow) and 512KB of SRAM (save ram, an eRAM designed for saves) which can store the ROMs of GBA games as well to make emulation nearly perfect by using Nintendo's own built in virtual console, also with rumble support