Help to choose a graphic card

I need a new graphic card, and your help Smile My budget is no more than $250. Just used for oclhashcat (no games).

As I understand the more important thing to check is the number given by
Quote:numberOfCores * ClockRate

I looked at this table : and I saw 2 cards :
Quote:Radeon HD 5870
Cores : 1600
ClockRate : 850
This card seems powerful, but quite old (released in Sept 2009)

And :
Quote:Sapphire HD 7770 OC
Cores : 640
ClockRate : 1150 (OC)
This card seems less powerful, but recent (released in feb 2012)

I read somewhere that 7xxx family have maybe less cores, but they are more efficient/powerful than older family (5xxx).
  • Is it true for oclhashcat work ?
  • Which one would you take ? And why ?

Thank you for your help.
I would save some more money and then take the hd7970
Thanks for your answer but.. if I don't want to put so many money in it, which one should I choose ?
of course hd 5870. it is faster in all counts
So whatever the family (5xxx,7xxx,..), the most important thing remains the largest ratio numberOfCores*ClockRate.
yes, exactly.