PSU (+12v = A32) , (+12v = -)

im building a budget pc, the psu that comes with the case is 500w but does not tell voltage specs, so im buying a separete one. BUT the one that i found has a - (dash) through the number underneath the 2nd +12V number. so whats that mean?

i need to know if this psu can power an OCed 7950gt 256mb, too.

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2227022&sku=GEN-2004

There is only one +12v rail.
It has a max output of 384w on the +12v rail.

That is a very cheap budget PSU, not too much quality there.

alright, well what about this one? and are the amps that important? becuase this card is the exact minimum a 7900gs can take.

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2974303&CatId=106