Comparing processors is tricky. It is more than speed. It is necessary to verify the amount of Cores, amount of cache memory, the type of memories supported by the processor. Pay attention to technologies embedded like Hyper-Treading.
Now, if we compare processors from the same generation, i5 processors usually run faster than i3 and usually have more cache memory.
If we compare processors from different generation, it is possible to get i3 processors with better speed but they will support memory with less speed, less Cores, less cache, older graphics versions and they might support older PCIe technologies as well USB technologies.
I recommend you to use our ARK website to compare Intel® processors.
The suggested price of both processors is the same. Intel® Core™ i5-6200U has Intel® Turbo Boost Technology, it means the processor speed changes if system requires more power. It changes from 2.3GHz to 2.8GHz. Please check the comparison.
Both processors are available in OEM laptops only. It will be necessary to review and compare the components of each laptop.