Coming in really late to the game since I'm new here and all, but since this is a stickied thread, 'necroing' this thread from the dead shouldn't be too big a deal especially since the issue is still as important as it ever was.
Another way to tell that the Memory Stick is bad (fake or just simply DOA/Dead On Arrival) is to format the Memory Stick and see if it formats properly and gives you the proper memory space.
Especially for the 4GB+ (4, 8, 16GB etc) Memory Sticks, all too often, the fakes will be unable to format properly leaving you with either NO space or way LESS space than there should be. Also, checking to see if what your PSP says about how much 'Stick space there is matches what your PC says is another way to possibly tell because again, oftentimes there are discrepancies with fake 'Sticks.
If you are experiencing issues with corrupted save files or corrupted data on your 'Stick for no explainable reason, that is another warning sign to be aware of as well.
And yes, where not ALL fake Memory Sticks are 'bad', the last thing anyone needs is for their PSN downloaded game to suddenly be wiped out/corrupted because suddenly, the fake Memory Stick GOES bad.
This isn't to say that genuine Memory Sticks DON'T go bad, but if it goes bad within a certain period of time, it is at least possible to return, exchange, or file for the warranty/guarantee which is something you CAN'T do for a fake.
Besides my PSP 3000, I've used Memory Sticks (the original Memory Stick up to the Pro Duo) since the beginning because I owned a lot of Sony gear (Clie, in this case) that used Memory Sticks. Because of this, I've had a lot of experience with the good, the bad, and the ugly when it comes to good and bad 'Sticks.
The real moral of the story is this:
The fakes are CHEAP for a REASON. Their reliability can NOT be counted upon especially if the information you are storing on them is important.
If you are one of the people whose fake Memory Stick has managed to hold out beyond a few months of continuous use, then you are one of the FEW. Be wary of that, not proud, because one of these days, your luck quite possibly WILL run out and you will have no recourse for it because rescuing data on a crapped out 'Stick is a major pain in the ass if it is even rescue-worthy in the first place.EDIT:
A GREAT time to buy a cheap Memory Stick Pro Duo supported up to 16 Gigs is online and during Black Friday (for those in the USA). I purchased a 16 Gig Sony branded Memory Stick Pro Duo for $32 + shipping + taxes during 2010's Black Friday.
5546170 16GB MSPD MARK 2 SONY MSMT16G 1 $32.00 $32.00
Thanks again for placing your order with us! Subtotal: $32.00
Net Product: $32.00 Shipping and Handling: $1.99 Sales Tax: $3.31 Order Total: $37.30
Edited by CollectiCopia, 26 April 2011 - 11:14 AM.