u can oc it to 256mb speeds, but u cant add more ram to a video card if that's what your asking, but u can easily oc the 5200 past the 256mb version, on my 5200 i got it up to 300/400.
Ridlyn just told you, you cant add more RAM to the card because that is what your saying. If your trying to overclock to the speeds of a 5200 256mb, try rivatuner or coolbits. I beleive both of these will work (someone correct me if im wrong though).
u can oc it to 256mb speeds, but u cant add more ram to a video card if that's what your asking, but u can easily oc the 5200 past the 256mb version, on my 5200 i got it up to 300/400.