1. A system for computing a vertex or pixel value, comprising: a plurality of processors of a same processor type arranged in parallel and configured to operate on the same vertex or pixel, each processor of the plurality of processors configured to execute a segment of executable code constituting a part of a single vertex or shader program, wherein the plurality of processors compute a respective plurality of transformed or rasterized results for the same vertex or pixel; and a combiner configured to combine the transformed or rasterized results from said plurality of processors to produce the vertex or pixel value.