Unless the idle hyperthreads are on different cores, you'd most likely have the same execution results. Using idle cores could be interesting, but your thermal

Unless the idle hyperthreads are on different cores, you'd most likely have the same execution results. Using idle cores could be interesting, but your thermal and power budget would be shared so your overall performance would still decrease. This is probably difficult to do at a fine grained level, but I imagine that coarser synchronization and checks (both in software) could provide the necessary assurances that code executing on a single core is consistent with that of other cores.