If you look at the properties it should tell you the connection speed. You will see numbers like 300,433,867. See if you get different numbers on the laptop and the desktop. This represent how good the signal is and the method being used to encode the data. You want to see if the numbers are different.
One of the big things that could be happening is that your desktop is connecting to the 2.4g radio and the laptop is connecting to the 5g radio or the reverse. Be sure it connects correctly. You really should use different SSID for the 2.4 and 5g radios in your router so you can control this. The default on many routers is to use the same SSID.
That card is fine it antenna that tend to be the issue. On a laptop the...