Single core jump should remain the same of course, but multicore more with rumored 12 cores instead of 10 (I expect 25% instead of 18%),
If those two added cores are presumed to be p-cores (are they? I can't find much info on that), that's a 10+2 instead of 8+2 setup. If we assume the same clock rate bump, that would indeed be a 38% improvement.
Of course, as always with additional CPU cores, diminishing returns.
plus the GPUs will be significantly faster and also more of them.
Sure, GPU is a different matter. So is e-core speed.