According to this subreddit, players are experiencing different bugs, but relevant frame drops while playing is the most severe one. It doesn't matter what kind of CPU or internet speed they have. It seems to be an issue from the game itself.
The website Dexerto shared a few steps users can follow to fix the FPS problem.
- Launch Valorant, and minimize the game
- Open your Task Manager (by right clicking the Windows Task Bar and clicking “Task Manager”)
- Click “More details”, and select the “Processes” tab
- Right click Valorant, and select “Go to details”
- Right click “VALORANT-WIN64-Shipping.exe”, and select “Set Affinity”
- A window will pop up showing which CPU threads are currently enabled for Valorant. If they’re all checked, this fix probably doesn’t apply to you. If there’s only a couple checked off and everything else is unchecked? Check the box “<All Processors>” and click OK
- Repeat steps #5 and #6, but on “VALORANT.exe”