Identify this saturn cart, cause I cant!

I picked up a saturn cart a while back, plain white with no label. It seems to have save space on it and the title on the menu is "madness action replay" by ems. ems has two models they sell (as far as I can tell), one has 1m expansion, the other has 4m. how do I tell which one I have?
With a title like that it doesn't sound like it's either cart.

If you can, try booting a 1MB game and a 4MB game and see what happens.