Ropz is talking about this sequence : https://x.com/ropz/status/1958654025504891361?s=46
For those without Twitter, in this sequence he's rotating from ramp to heaven as Tyloo are rushing A.
When he's at ramp, he has like 600 fps, and when he turned and went under heaven (during the match), he immediately got down to around 130 fps (note : that means he could not even see any flash, smoke or molly thrown on A yet).
In the comments, there's plenty of people replicating it with the demo and even with a 9800x3D and 5070's/5080's (note : this tournament has an Intel CPU which is not as good for CS2 as the 9800x3D, but still a top of the line CPU), they still get max like 150-160fps on that rotate in the demo, for no reason.