Interesting.
My Fathers house.
100/100 fiber service -gigabit to-> WNDR3700, DDWRT, wifi disabled -100base to-> 3 airport expresses extending wifi.
The WNDR3700 supplies DHCP and routing. We used to use its wifi, but could never get WDS working reliably. Hence the 3 airport express hotspots.
Desktop gigabit into WNDR3700 could speedtest 112/101.
2x2 MIMO IPad Air into 2x2 Airports due to overhead and the 100mb interface, should have only been able to speedtest 80/80. But it actually hit 93/83, see earlier in thread.
Turned on its 2x2 wifi 5ghz on the WNDR and set a channel far from the airports to take advantage of its gigabit link. ~60mbps speedtest, only linking as if 1x1.
No clue why. IPad Air may not be playing perfectly with non-Apple access points.
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Caution.
Dual band
Simultaneous dual band
dual spacial stream / 2x2 or 3x3 / MIMO
Are 3 different things.
IPad Air is Dual Band (not-simultaneous), MIMO 2x2.
Asus n56u is. Dual Band, Simultaneous, MIMO 2x2.
It *should* work. It *didn't* work with Dad's ASUS.