Something to think about regarding the number of CPU cores and laptops/desktops.
In the desktop version, i5 and higher are usually quad-core, but in laptops, you could only end up with a dual core. They do that for power saving and extended battery life, but at the potential expense of performance.
For instance I have an i5 laptop (non DAW), but it is only dual core with 1.7GHz turbo to 2.5Ghz. It is slower than my i3 desktop (DAW), which is dual core and locked to 3.4 GHz. Both have 4 threads due to hyperthreading.
So I would say at least an i5 quad-core in the 3-4 GHz range would be worth looking at.
The clock speed is the bottom line as far as how fast a single thread can perform. The more cores/threads you throw at it, the more work your CPU can do concurrently. The i7 is ideal for a heavily loaded Sonar DAW due to the plugin load balancing with 4 cores/8 threads.
But is up to the software developer to take advantage of multiple cores/threads. A badly coded app that is single threaded can only run as fast as your max CPU clock speed. The other cores will not help in that case.