WIFI only at 400Mbps Sophos AP55

Question

Dear all 
 
 I just bought a AP55 and according to sophos its radio type is 802.11ac 
 But my MacBook Pro and Google Pixel can only connect at 400Mbps speed. 
 Both my MBP and Google Pixel supports 802.11ac, when MBP connects to AP55 connection details shows AP PHY type is 802.11ac but I just don't understand why only 400Mbps 
 any idea? 
 
 thanks

Usbkey · Accepted Answer

XG 17.0.5 MR5 added 80Mhz channel option. 
 
 Now 5G WIFI connection at 866M as specified in AP55 spec. 
 
 Problem solved and Thanks Sophos.

David Birdsall · Answer

Usbkey said: 
 Dear all 
 I just bought a AP55 and according to sophos its radio type is 802.11ac 
 But my MacBook Pro and Google Pixel can only connect at 400Mbps speed. 
 Both my MBP and Google Pixel supports 802.11ac, when MBP connects to AP55 connection details shows AP PHY type is 802.11ac but I just don't understand why only 400Mbps 
 any idea? 
 thanks 
 
 USBKey, 
 I am not sure how you are determining this 400Mbps number. Is this the overall wireless connection speed between device and AP, or is it a measure of throughout to an internal network or external internet source (though the AP-wireless/wired network and Sophos/security devices)? 
 
 This issue depends on several things: 
 1. On the Wi-Fi side of the issue, The MacBook Pro is a 3x3 device. The AP55 is only 2x2. This means the AP55 can only provide 2/3 of the maximum Wi-Fi capability of the MBP. This may only be part of the issue. 
 
 The other side of the issue may be your Sophos device or whatever firewall/security device you use (if you're using Sophos Cloud Wi-Fi). There are two possible problems here: 
 2. The main issue is that your Sophos SG UTM or XG Firewall (or other firewall/security device) may not be sized properly to be able to handle all of your network traffic and connections at maximum speeds and throughputs. Each model has certain physical speed/throughput limitations. 
 3. The other issue is that each Sophos UTM/Firewall model also has certain software limitations as well. Certain features, when activated in the SG UTM and SG Firewall, slows down the traffic flowing through it. If you are using Cloud Wi-Fi, then the firewall you are going through is slowing down certain traffic as it tries to scan the traffic while en route. 
 
 Depending on your particular setup, settings, and testing, you may get different results regardless of top theoretical speeds possible. For example: 
 I am currently on a system that has a an Apple Time Capsule (tower) in bridge mode connected to an SG Firewall. The Time Capsule AP and the MBP are both are 3x3 AC, so the Wi-Fi connects to my MBP at full 1.3Gbps. When I test using an internet based test that goes through the AP, the network, and the Firewall to the internet, I only get a maximum of 350Mbps. That's because the internet service here is 350Mbps. 
 I can get even slower results: 
 When When I activate Scanning FTP for malware in the SG Firewall, the Ookla Speedtest app on my MBP is limited to 100Mbps while the Ookla website http://beta.speedtest.net measures the full 350Mbps internet service here. This is because the because the macOS App uses FTP while the website is using a different file transfer protocol that bypasses my FTP scanning. 
 *The Time Capsule AP provides a combined 20Mhz/40Mhz/80Mhz side signal, but most apple devices only us 40Mhz. Setting your Wi-Fi to 40Mhz may also help with some Apple Wi-Fi issues.

Channel Width	Valid Channel Numbers
20 MHz	36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 149, 153, 161, 165, 169
40 MHz	38, 46, 54, 62, 102, 110, 118, 126, 134, 142, 151, 159
80 MHz	42, 58, 106, 122, 138, 155
160 MHz	50, 114