When processors stopped getting any faster (per their gigahertz rating), we were told that multi-core was the way of the future. We were told that we would be using 4, 8, 16, even 32 core CPUs. But we're still stuck with dual core for the most part and quad core for high performance applications.
And didn't AMD already have an octa core CPU out a couple of years ago?
To be fair, intel has hyperthreading. So, really, an octa-core is more like a 16 core processor. Also, intel has been working on the architecture. Intel blows AMD away at IPC, so 1 ghz intel vs 1 ghz amd, intel wins hands down.
Also, I don't know a lot of people with just dual cores, mostly quad and hex core machines.
ALSO, on server side of things, intel has a 10 core processor w/ hyperthreading that supports up to 8 sockets and 4 TB of RAM. So, you can have 80 cores / 160 threads on a single board w/ 4 TB of memory.