Jan Gray wrote an excellent essay ... My favorite quote from this piece is "This scenario is so bad and so common that the microprocessor vendors use 80% of their transistor budgets for on-chip caches -- Intel as glorified [SRAM]{.caps} vendor.". via [iunknown.com]
This echos a favorite theme of mine: most discussions of performance ignore the differing costs of memory access. To the extent that people think about it, they split the world into RAM and disk, when it's much more productive to think of a series of ziggurat-like steps that extend all the way from the CPU registers to the Internet and offline storage. (BTW, the essay is a year old, which makes some of the references, especially to C#'s closure support, a little odd).