Explore the importance of efficiency in modern C++ programming through this comprehensive conference talk from C++Now 2018. Delve into the misconception that performance no longer matters due to advanced hardware, and discover why computers often feel slower today than 30 years ago. Learn about efficiency tools in modern C++ and techniques for writing high-performance code elegantly and expressively. Cover topics such as tuning vs. optimizing, value vs. reference semantics, unions and variants, move semantics, forwarding, container choice, in-place construction, and container node handling. Gain insights on writing optimal code, compiler optimizations, caches, dynamic and static allocation, passing and returning values, perfect forwarding, and choosing the right containers for your needs.