It is "only" 50x because a single GPU core is 100x weaker than a CPU core!
Within CUDA cores, it is actually a linear speedup! It does 2k MIPS with 1 CUDA core, and ~28000 MIPS with 16k CUDA cores. If we double the performance of single-core GPU evaluation, we almost double the performance with 16k cores!
It is "only" 50x because a single GPU core is 100x weaker than a CPU core!
Within CUDA cores, it is actually a linear speedup! It does 2k MIPS with 1 CUDA core, and ~28000 MIPS with 16k CUDA cores. If we double the performance of single-core GPU evaluation, we almost double the performance with 16k cores!