Software defined radio (SDR) systems require programmable architectures that provide high performance combined with high energy efficiency. Wide single instruction, multiple data (SIMD) architectures could potentially satisfy these demands, but only few publications examine the interdependence between the SIMD width and the performance of typical SDR algorithms. In this paper, we present a detailed analysis of three SDR algorithm classes on a newly developed scalable SIMD architecture. Although radix-2 and mixed-radix fast Fourier transform, sphere decoding, and low-density parity-check decoding all benefit from SIMD processing, our results show that there are different constraints on the performance. If the constraints are fulfilled, all implemented algorithms achieve close to linear speed ups.