A task identifier-based mechanism is configured to temporarily disable a dual-issue capability of one or more threads in a superscalar simultaneous multi-threaded core. The core executes a first thread and a second thread which are each provided with a dual-issue capability wherein up to two instructions may be issued in parallel. In response to a task identifier being received that is indicative of a task requiring an improved level of determinism, the dual-issue capability of at least one of the first thread or the second thread is temporarily disabled.