Sounds similar to what I’ve been experiencing
I’m 99% sure its something to do with EVE.
I’ve reinstalled everything apart from Windows and applied every tweak I can come across online and nothing seems to fix the problem.
I can sit on Jita/Perimeter gate with CTRL-F open and watch the dips every time some jumps in/out of system or warps to the gate.
Jumping through this gate in particular from either side brings my FPS to 0.
Almost like a crash.
And then it ramps back up again after a few seconds.
I’ve had the issue since the new jump animation patch.
Been living with it since.
Ticket was useless, they advised to report as a bug so the Game Designers pick it up and not the Devs.