1.3Gbps is achieved using 3x3:3 at 80MHz channel width.
That's transmitting on 3 antennae, receiving on 3 antennae with 3 parallel streams of data.
From reading the specification data sheet shared in the link above, it appears that this Intel card is capable of 2x2.
The same data rate can be achieved using 2 antennae, but only when using a channel width of 160MHz, which is not supported by the Ruckus R600.