Sadly yes... I've seen counterfeit 8GB mem sticks (and even bought one by mistake)... I use it one my psp and it was one of the worst gaming experience I had. FMVs lag so much and loading time was dead long...
I have a PS2 and the last time I used it was a couple of months ago since I wanted to play Dirge of Cerberus again. Still played fine after about a year of not using it. But I made sure to keep it away from dust and other things.