Hello. For a while now I have been using an old wifi router that connects to my modem for a 2ghz connection. It wasn’t until recently that I discovered I actually had built in 5ghz wifi on my modem! I couldn’t connect to it because my wifi card in my desktop only supported 2ghz, so I bought a 5ghz card and connected. However, everytime I’ve tried to run a speedtest on speedtest.net, it’ll go up to about 100mbps(which is WAY faster than my 2ghz was giving me) but then the number will steadily go down over about 10 seconds all the way back to 0mbps, and then the internet no longer works, and I have to run the windows diagnostic tool for it to work again. So far, I have tried: flushing my dns, updating/restarting the modem, updating my wifi adapter, changing the channel on the modem at which the 5ghz wifi broadcasts on, disabling the ’turn off this wifi device to save power’ in windows, and nothing has worked.Occasionally I can run a full speedtest with no crashing, but if I try to run a second speedtest right after, it will crash. I also tried playing a video on youtube and when I switched to 1080p the internet crashed again. Also, if I switch back to the old 2ghz wifi router, I have no disconnect issues.The modem I am connecting to is a default modem given to me by spectrum which has 5ghz wifi built in.