Yes, I tried different notebooks, all of them are running 2x2 MIMO on RX site (so I get 130/65), one of them also on TX site (also 130/130 rates).
With RB433 and R52Hn its ok, with RB 751 only 65/65 rates.

What is your RB751 setup (antenna, MCS rates etc.)?

Hi, in recent months I tested RB751G/RB751U wireless performance. Even with DYI antennas, or with external antenna, or with original PIF antennas. With better antennas, the router is working fine with great range, BUT: I can't set it to work in 2x2 MIMO mode. On 20 MHz channel, I get only 65/65 Mbit...

I did those tests with speedtest mini running on our main server, also it was real traffic. UBNT itself has speed test (it can measure speed to another UBNT in the network), but its measuring UDP only. Although, this UDP speed measured with UBNT is high, about 40-50 Mbps one way, so I am curious, wh...

No, WDS is disabled. The performance problems with 802.11n MIMO were also in v4.11, so I upgraded to the latest version (thinking it would be better with MIMO). But no difference at all. When I have UBNT to UBNT on 20 MHz, it is running 30-40 mbps without AirMax and 50 (sometimes 60) mbps with AirMa...

You havn't applied "HT extention channel: above control" under HT.

Do this for both AP and client

RGDS

Yes, I haven´t, but I dont want 40 MHz channel (extension channel makes 40 MHz bandwidth).
But also with 20 MHz the TCP troughput should be cca. 40 Mbps, not 22/16...

Hello, on our site we use RB433AH with R52Hn and UBNT MIMO Sector 16dbi/120deg. Both chains enabled, also 2x2 MIMO. Clients are located 100-800 m from the AP and have UBNT devices (NanobridgeM5, NanostationM5). Signal for all clients is clear, from -45 to -55 dB on both sides. It´s linked together o...