These microcode patches don't turn off speculative execution, they only give a way for the operating system to temporarily and/or partially turn it off and/or f

These microcode patches don't turn off speculative execution, they only give a way for the operating system to temporarily and/or partially turn it off and/or flush the branch prediction state (precise explanations are hard to come by). This is why benchmarks which use more heavily the operating system are affected the most, while benchmarks which stay in user mode doing computations are affected the least.