Add note about send and recv buffer sizing

Author: Brett Witherspoon

quick-start-guides/usrp-x410.md

@@ -171,7 +171,9 @@ usrp_update_fs -t v4.5.0.0
 ssh-keygen -f "$HOME/.ssh/known_hosts" -R "x410-0"
 ssh root@x410-0
 mender commit
+```
 
+The UHD driver will strongly suggest that the networking subsystem send and recv buffers are sized sufficiently.
 
 ```shell
 [WARNING] [UDP] The recv buffer could not be resized sufficiently.
@@ -187,6 +189,8 @@ See the transport application notes on buffer resizing.
 Please run: sudo sysctl -w net.core.wmem_max=2500000
 ```
 
+The UHD package installs a `/etc/sysctl.d/uhd-usrp2.conf` to adjust these settings on boot, but these values are for the older gigabet Ethernet devices and need to be increased.
+
 ### References
 
 - [Product Page](https://www.ettus.com/all-products/usrp-x410/)