About once or twice a day SmartSDR loses connection with the 6400. I'm not doing anything, just listening to 40 meters. It's the same LAN setup (four port switch) I had with my 6300. The 6300 never lost connection.
Look at your task manager under performance and watch the graph of the CPU utilization. If it hits 100% for a little bit. since it cant communicate it will loose the connection. If you have a separate graphics card less of a problem but have seen this happen. The graphics uses a lot of resources. More panadapters open the more the screen is constantly updated. Chrome kills my resources too. my video interface is onboard, not the best. SmartSDR seems to be more like a gaming computer than just internet and email. My computer is a Dell Laptop Inspiron I5 3210M processor with *GB of RAMM. I have to be careful what I have up on the screen or it runs out of CPU and disconnects the radio.
Bill, thanks for the suggestions. I did have FireFox open - and yes it takes it's share of the CPU resource. Graphics is built-in. At your suggestion I looked at Task Manager - CPU usage and it's just 6% total. However, Memory is at 51%!. Perhaps I should upgrade the 8GB to 16...
Another thing you might check is under Device Manager. Make sure that your LAN card is not set to "green" mode that turns it off when the system doesn't see a lot of activity. Every once in a while, Windows 10 updates my system and sets my LAN card and other subsystems to green mode. #$%^ tree huggers!