The surprising results of a performance comparison between std::vector<> operator= and memcpy() with a raw array. An application profiling effort by a colleague and I led us to investigate the performance tradeoffs between std::vector<> and a raw array ( uint8_t blah[] ). The application was a c++ rewrite of a c# application. The rewrite was undertaken because the overhead of running a c# application on our memory and cpu constrained ARM Linux system was affecting system performance and responsiveness. Using Mono to run C# applications on Linux resulted in ~40MB of ram overhead for our application that itself allocated tens of thousands of bytes at most. Startup time left much to be desired. It took a few seconds to start the application up from mmc on the 1GHz ARM processor. We verified the long startup time by printing an “I’m started” string as the first function in Main. We tried upgrading to a newer version of Mono to see if that would improve performance. We las