pi5 with active cooler is about 1.2-1.5x faster than pi5 without cooler for most workloads that care than without.
Pi5 with active cooler is about 2-2.5x faster than Pi4. So Pi5 without cooler is probably about 1.5x faster than pi4, depending upon workload. (And more than this for quick bursts where thermal mass wins).
The actual info I'd rely upon at this point:
https://www.phoronix.com/benchmark/result/raspberry-pi-5-coo...
pi5 with active cooler is about 1.2-1.5x faster than pi5 without cooler for most workloads that care than without.
Pi5 with active cooler is about 2-2.5x faster than Pi4. So Pi5 without cooler is probably about 1.5x faster than pi4, depending upon workload. (And more than this for quick bursts where thermal mass wins).