Controller Based WLANs

With 802.11n, 600Mbps can be achieved with 4 spatial streams.
For 802.11ac, the important contributing factors are:

1. 256 QAM – Provides 33.37% increase in throughput
2. 160 MHz – Multiples the existing capacity in 20MHz channel by 9 times
3. 8 Spatial Streams – Multiplies the throughput by 8 times

Maximum data rate achieved by 802.11n with MCS 7, 1 Spatial Stream and 20 MHz is 72.2Mbps.

So improvement provided by 11ac is:
72.2 * 1.3337 * 9 * 8 = 6933 Mbps (Max with 160 MHz and 8 SS)