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Premature and/or over-optimization is often claimed to be a root of most evil in the programming world. However, what to do when optimization IS neccessary?

IT Hares discuss certain not-so-trivial optimization techniques. It doesn’t mean that you should use them at all costs (and most likely, you don’t); however, if you do have a reason to optimize – this information may be handy.

Optimizations, page 1:

Ultra-fast Serialization of C++ Objects

Quote: “in both these cases we can be 100% sure that we’ll be deserializing this state on the executable which is identical to the executable which serialized the state.”
Another Quote: “Even when comparing with home-grown code with per-field serialization, our Ultra-Fast Serialization still wins (up to 1.5x-2x) “

Some Big-Os are Bigger Than Others

Quote: “Strictly speaking, for real-world computers, every algorithm which completes in a finite time can be said to be O(1)
Another Quote: “now the difference because of unfortunate ‘jumps’ over (uncached at the time) memory can lead to a 100x+ (!) performance difference. However, it is still O(1) and is rarely taken into account during performance analysis”

C++ Performance: Common Wisdoms and Common “Wisdoms”

Quote: “over(ab)using C++ features is a different story, we’ll discuss these features below on case-by-case basis”
Another Quote: “Compiler will use all its Next-to-Divine Wisdom to show you that it is smarter than you are, and to ignore most of those inline specifications you carefully wrote.”

C++ for Games: Performance. Allocations and Data Locality

Abstract: “Allocations and related lack of spatial locality can be DAMN EXPENSIVE”
Quote: “During the times of Ancient Gamers (also known as times of Atari, ZX Spectrum, and Commodore64), CPUs were running at clock speed of a single-MHz (and one operation usually took several clocks). At the same time, memory run at about the speed comparable to that of CPUs.”