Just as an FYI, the infiniband drivers that come with RHEL/CentOS 6.4 should work perfectly with your cards:
$ sudo yum groupinstall "Infiniband Support"
Apparently they're not as optimised for some things as the Mellanox OFED stack (I don't know the details), but for just general day to day stuff they should be fine.
Note, I think you'll need to uninstall the Mellanox OFED stack first, before installing the built in ones.
Hope that helps.