How are your respective gaming tower positioned?
For example - is your gaming tower physically between her gaming tower and the router? Or some other notable difference is location with respect to the wireless router?
Ensure that she has only one network adapter enabled. Either wired or wireless - not both. In her system only the wireless network adapter should be enabled.
Are both wireless adapters installed with the current drivers? If not, manually update her drivers to match yours (if and as applicable). Do not use third party driver installers. Manually download the drivers via the manufacturer's website (Intel), reinstall, and reconfigure.
Compare the wireless network adapter configuration settings between the two systems. The configuration settings should be very similar but there will be some differences.
Investigate any configuration differences to determine what functionalities are being affected. ( For example, as mentioned by
@Secret-Squirrel, the towers may well on different frequencies and channels. Her tower's frequency and channel being more subject to interference perhaps.)