How much slower? - we diable speculative execution, so every conditional branch goes for 1 cycle to the pipeline depth (5, 10, 20 cycles) to evaluate. Probably

How much slower? - we diable speculative execution, so every conditional branch goes for 1 cycle to the pipeline depth (5, 10, 20 cycles) to evaluate. Probably a 2x to 3x hit on performance. - we disable prefetching, so every cache miss now has the full memory latency delay to fill a cache line. 1.2 to 1.3x hit??? - We disable SIMD as per this issue. 4x-8x hit on those parts of the code that usebit. - If we need to go as far as disabling caching you can now only run instructions at the speed of main memory. 100x hit. CPUs would only be faster than their 1970s ancestors because the clock speed was now 5GHz and not 1 MGHz.