In the week or so that I've had my new 13" MBP, I've had several episodes when the WiFi degrades severely. I'm in the same room as the AP, with a strong signal (around -40), and the TxRate in the WiFi menubar dropdown typically is in the 650-867 range (with actual tested LAN speed being in the ballpark of 300-450Mbs). But every now and then, the connection speed will plummet, showing about 13-50Mbs TxRate and a similar actual speed. During these slowdowns, if I test on other devices they are still running at full speed, so it's not a router issue.
Sometimes it will clear on its own after 20-30 minutes or so, but a simple cycling of WiFi power or disconnected/reconnecting to the network will instantly restore full speed, which would seem to disprove the possibility that there is persistent external interference causing the speed to drop (otherwise, why would simply reconnecting result in full speed returning?).
Another member pointed out that the MBP uses the same new WiFi chip as the iMac Pro, so I disconnected the ethernet and started scrutinizing this machine a bit closer (I've almost always used it just on ethernet). Sure enough, it is exhibiting similar behavior.
During this testing I also brought in my daughter's 2017 MBA and have had it running here on my desk for almost 24 hours (during which time the MBP and iMac Pro have had several episodes of slowdowns), but the MBA's WiFi has remained rock solid, so I don't think it's a problem with my router nor with interference, unless this new WiFi chip is hyper-sensitive to interference (and remains stuck in a slowed-down state even if the temporary interference is gone).
I should note that I did observe strange WiFi behavior when I first bought the iMac Pro in December, as others observed too... it would show a really low TxRate in the menubar, but actual transfer speed would be normal (looks like an OS update must have resolved this, as it no longer seems to be the case). But this is different... it shows full speed in the WiFi menu and tests at full speed, but encounters periods when the speed (indicated in the WiFi menu, and actual speed) drops considerably for an extended period of time.
Sometimes it will clear on its own after 20-30 minutes or so, but a simple cycling of WiFi power or disconnected/reconnecting to the network will instantly restore full speed, which would seem to disprove the possibility that there is persistent external interference causing the speed to drop (otherwise, why would simply reconnecting result in full speed returning?).
Another member pointed out that the MBP uses the same new WiFi chip as the iMac Pro, so I disconnected the ethernet and started scrutinizing this machine a bit closer (I've almost always used it just on ethernet). Sure enough, it is exhibiting similar behavior.
During this testing I also brought in my daughter's 2017 MBA and have had it running here on my desk for almost 24 hours (during which time the MBP and iMac Pro have had several episodes of slowdowns), but the MBA's WiFi has remained rock solid, so I don't think it's a problem with my router nor with interference, unless this new WiFi chip is hyper-sensitive to interference (and remains stuck in a slowed-down state even if the temporary interference is gone).
I should note that I did observe strange WiFi behavior when I first bought the iMac Pro in December, as others observed too... it would show a really low TxRate in the menubar, but actual transfer speed would be normal (looks like an OS update must have resolved this, as it no longer seems to be the case). But this is different... it shows full speed in the WiFi menu and tests at full speed, but encounters periods when the speed (indicated in the WiFi menu, and actual speed) drops considerably for an extended period of time.