It depends on what/how you're comparing. Core to core, according to CPU benchmark, the M1 is 5800 vs the M5 at 3600, so we're still not quite to 2x.

Overall system performance is better at about 2x improvement thanks to extra cores/other improvements/changes. I could see other more specialized benchmarks improving more thanks to different improvements/core/power/size improvements in other components (GPU/NPU/etc...).