There are folks running DAWs on AMD, but for low latency audio, it seems that Intel has the edge.
I have a 3rd gen Intel Core i3 that I built a few years ago that is perfect for home recording. I get low latency and it is capable of many more tracks than I care to manage.
I have always used Intel, since the Pentium 1 days, so I don't really know much about the AMD nomenclature.
As far as Intel goes, the i3 desktop CPU is half of an i7, so instead of 4 cores and 8 threads, you get two cores and 4 threads. The desktop i5 scales up with 4 cores, but just 4 threads. The price goes up quickly though.
If your demands are going to be moderate, get the latest gen Core i3 with the fastest clock you can afford. I have been running my 3.4GHz CPU which rarely goes over 50% with what I do. Usually much lower, in fact.
The thing to remember is that a single thread can only run as fast as the CPU clock, so that is the speed limit. Good software developers in some cases have learned how to split up their workload across multiple cores and threads, so in that case a quad core can outperform a dual core. But the real difference comes down to how heavy you plan to use the system. Sonar is one application that can take advantage of that and spread the load.
Sure you could buy an i7 and many will say you need it. But unless you plan to run dozens of tracks with multiple plugin effects on each one, you probably can get by fine with an i3 for what you say you need. It's not a crippled CPU by any measure, it's just that you often see them in cheaply made off-the-shelf PC's, so they have a certain reputation. But if you pick a quality motherboard, power supply, RAM, you should be good. And start out with an SSD for the OS drive, the prices on those are very affordable now. That gives a huge boost to system responsiveness!!!
You can compare prices here:http://pcpartpicker.com/list/