I guess the 2nd option is better, it has a bigger fan...
One thing worth noting is that the non reference version is likely going to vent more air into the case. The fan is placed in the middle, which will push air out both sides of the card. It shouldn't be a problem if you have a good case and fan setup.
^+1, also the second version is cheaper, (does not come with backplate either) which may mean that the cooling system may be as sufficient and quieter, but will, as bystander said, vent more hot air into your case.
Thanks for your help.
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