Multi-core processors are now common but musical and audio applications that take advantage of multiple cores are rare. The most popular music software programming environments are sequential in character and provide only a modicum of support for the efficiencies to be gained from parallelization. We provide a brief summary of existing facilities in the most popular languages and provide examples of parallel implementations of some key algorithms in computer music such as partitioned convolution and non-negative matrix factorization NMF. We follow with a brief description of the SEJITS approach to providing support between the productivity layer languages used by musicians and related domain experts and efficient parallel implementations. We also consider the importance of I/O in computer architectures for music and audio application. We lament the fact that current GPU architectures as delivered in desk and laptop processors are not properly harnessed for low-latency real-time audio applications.