Read the link, it doesn't do anything to you DS.
SRAM stands for Save RAM and is the RAM in GBA cartridges used for saving.
The only thing it would do is clear that, and that doesn't affect DS games.
I think it only works with a flash cart in Slot 2 and doesn't do anything to a regular GBA game.
So the slow down you noticed is most likely just in your mind. Which is ok, your mind can play you such tricks when you panic.