Hi I’m a very new Linux and Manjaro. I’m using my PC mostly for gaming and something strange occur.
Whenever I’m playing a game and receiving a discord notification (like messages) make game lag for a second. I disable notification but I wounder if there is another solution.
Welcome to the Manjaro community
As a new or infrequent forum user, please take some time to familiarise yourself with Forum requirements, and the many ways to use the forum to your benefit:
The Update Announcements contain important information and a Known Issues and Solutions section that should generally be checked before posting a request for support.
Output of this command (formatted according to forum requirements) may be useful for those wishing to help:
inxi --filter --verbosity=8
or the short form:
inxi -zv8
Be prepared to provide more information and outputs from other commands whenever asked. It’s equally important to provide as much actionable information as possible in your first post, rather than simply indicating there is a problem.
Regards.
Any network traffic can potentially do that. How bad thye effect depends on many factors, like how long the connection was established, the respective bandwidth, and the amount of data transferred in the background.
Applications that periodically check online (for any reason) might cause this annoyance. You could disable your Internet while playing a game, but naturally that’s pointless if your game needs to be connected. 
Please always add system information as described by @scotty65 any time you create a Support topic.
Regards.
