For normal program code it is closer to a Pi 4 than to a Pi 3, similar to the all the very popular A55s board that have come out more recently than the Pi 4.
The only way it is slower than a Pi 3 is if the Pi 3 program is using SIMD (Neon), which the VisionFive 2 lacks.
The worst part of this Pi 3 comparison is that the Pi 3 has only 512MB or 1GB of RAM, which is extremely limiting in the modern world. This RISC-V board comes with a *minimum* of 2GB and is available with 8GB for $37.
The RAM difference alone makes many things possible that are impossible on a Pi 3, and many other things much faster, regardless of the raw CPU speed.
And then you have the M.2 NVMe SSD, something that neither the Pi 3 nor Pi 4 support, which again makes a whole raft of things much faster, even if the single lane means it can "only" do something near 400 MB/s (vs SD cards at 40 or 80 MB/s)