SFV has an issue with at least some Nvidia cards/configurations where the drivers, in an attempt to save power (which is the default behavior), try to run the game on lower clock speeds. This causes momentary slowdowns (fps drop) when more power is needed, for example when your characters first appear on the character select screen, or when you transition from the loading screen to the actual match. To solve this:
Open the Nvidia Control Panel
Select "Manage 3D Settings" from the task list on the left
On the main window, now select the "Program Settings" tab that is on top
Just below that, select SFV's program from the drop down list, should be named "Street Fighter V (streetfighterv.exe)"
In the feature list below, now look for the "Power management mode" and select "Prefer maximum performance"
This will make it so your graphics card will always run on maximum clock speeds when SFV is running, preventing those slowdowns I explained above.
If this doesn't work for you, try to fiddle with Freesync. The game has native V-Sync and is super easy to run for your hardware, so Freesync is essentially worthless unless you go editing some files and remove both the frame cap and the native V-Sync, which is generally not recommended with the netcode being pretty finicky.