You can't determine performance based on frequency in the general case. If the CPU's are of the same family (not only same architecture) - by this I mean identical in every respect except for clock speed - then the maximum performance of the faster system will be faster, so yes, in your example the MAXIMUM speed of the CPU will be 12% faster.
But, of-course, this is nothing like the full story. Most systems will be bottlenecked by things other then CPU, in which case a faster CPU won't give you increased performance (for example if you are waiting on disk, networking or user input).
If the CPU's are not of the same line, the best you can do is get a rough estimation of performance by looking for the "Passmark" at CPU benchmark and computing based on that. This is very rough, but a better-then-nothing way of comparing CPU's once you understand how your application will handle threading. Also, comparing the CPU's in the Intel Ark will help you ascertain if they are the same in all respects other then clock speed. (For example by showing different instruction set support, cache etc)