Cool post, the mechanical sympathy group is all about exploiting today's CPU/Memory caches to their fullest usually referencing Java and C, great to see C# based examples of this.
I thought there might be something more insightful than this within the article. It's probably just because I happen to work in a field (HFT) that obsesses over memory access patterns. Cache hits are your best friend and they seem to be under-appreciated in the wider development community.
Check the linked video, it's a great talk on memory access patterns and why it matters. If you already know "everything" about it, then I guess there's not much new in my article but if you're like many of my co-workers, ordinary web developers some of this might come as a surprise.
I think performance optimization overall is under-appreciated in the wider development community, too many devs expect the runtime/compiler to solve it for them.