I've not got the numbers to hand between versions, but YJIT in Ruby 4.0 did shift the needle a bit, so yes, some gap closing. I also forget what the warmup was like, but to get 2-3x somewhat more was needed than with YJIT.

(Both running identical pure Ruby code, no extensions, in a long-running test scenario, no setup each time.)

Thanks for the detail. That is really a testament to how much better MRI has gotten...