What effect, if any, will this have on preexisting 3DS games? Will they run at a higher framerate? Will they be more stable? Or are the benefits of these hardware upgrades be limited to exclusive titles developed specifically with the new 3DS in mind?
Unless they're specifically patched, my guess would be that previous 3DS games will run in a "compatibility mode" that limits them to the original 3DS' clock speed and RAM.