A high throughput and scalable MIMO detector can use a K-Best detection algorithm to find K combinations of transmit symbols that are likely to be the symbols that were actually transmitted. The K-best MIMO detector can include a plurality of stages, where each stage may correspond to a transmit antenna, and each stage can find K best symbol combinations based on information from a previous stage. To find the new K best symbol combinations, at each stage, a plurality of metrics for potential combinations are computed and sorted by magnitude. The MIMO detector preferably uses a high throughput, merge sorting algorithm to sort the metrics.