[E6300]

An application being cache-unfriendly doesn't imply that it will be bandwidth-bound. If the application reads single words from random locations it will be cache-unfriendly and latency-bound. If it reads 1K contiguous bytes from random locations it will be cache-unfriendly and possibly bandwidth-bound. If it scans the entire memory space sufficiently quickly it may be both cache-friendly and still bandwidth-bound.

I can't speak for the server market, but I'm certain that the high-end desktop market is composed primarily of people who do run top-of-the-line specs just for fun.

[sliken]

Correct, an application that reads single words from random locations will be cache unfriendly and latency bound. However additional memory channels means you can run more of them and get better throughput.

Personally I bought more cores when I can and find that the average and best case are very similar to CPUs with less cores, but the worst case performance is much better. With 8 CPUs I find that the browser, plex, processing batches of photos, transcoding video, running a minecraft server and other random duties have much less of an impact on normal desktop use.

It used to be MUCH easier to be I/O bound with spinning disks, but with the new M.2 SSDs some pretty impressive I/O rates are possible (random or sequential), which makes it easier to be CPU limited.