I've always wondered, how many years difference is the latest smartphone processor compared to the latest desktop CPU? What I mean is this: For example, my phone has a Snapdragon 845 CPU. How far back would you have to go to the point where the latest Desktop CPU of that time is equal in performance to the SD845? Like how would it compare to an i5 2500K, or an old Core 2 Quad, or even a Pentium D in terms of clock rates, performance, IPC, etc? What old flagship Desktop CPU would be on par with the latest smartphone CPUs?