2014 MBP Retina WiFi keeps changing MCS

[JeffryA]

I use a Netgear R6700 running DD-WRT. The 5G band supports only AC, and my MBP is the only device using 5G. Sometimes it connects at MCS 7 and achieves 867 mbps. Other times it connects at MCS 9 and achieves 878 mbps. While the speeds are similar (and I'm not complaining), MCS 7 is using 3 spatial streams, but MCS 9 is using only two. I see the same RSSI and SNR at both MCS.

Any thoughts on why it goes back and forth?

Thanks for your help.

 

[Samuelsan2001]

I use a Netgear R6700 running DD-WRT. The 5G band supports only AC, and my MBP is the only device using 5G. Sometimes it connects at MCS 7 and achieves 867 mbps. Other times it connects at MCS 9 and achieves 878 mbps. While the speeds are similar (and I'm not complaining), MCS 7 is using 3 spatial streams, but MCS 9 is using only two. I see the same RSSI and SNR at both MCS.

Any thoughts on why it goes back and forth?

Thanks for your help.

No idea and with those numbers I see no reason to give a monkeys either.

 

[cbautis2]

The firmware knows what MCS level is the best at the moment. If it stays at the highest MCS, it would probably caused a higher error detection rate and you'll have dropped connections.