From July 2019: If looking at the geometric mean for these various mitigation-sensitive benchmarks, the default mitigations on the Core i9 9900K amounted to a

From July 2019: If looking at the geometric mean for these various mitigation-sensitive benchmarks, the default mitigations on the Core i9 9900K amounted to a 28% hit while the Ryzen 7 2700X saw a 5% hit with its default Spectre mitigations and the new Ryzen 7 3700X came in at 6% and the Ryzen 9 3900X at just over 5%. https://www.phoronix.com/scan.php?page=article&item=amd-zen2-spectre&num=3 https://www.phoronix.com/scan.php?page=article&item=amd-zen2... Should note: Keep in mind these benchmarks ran for this article were a good portion of synthetic tests and focused on workloads affected by Spectre/Meltdown/L1TF/Zombieload. Many of these particular tests aren't multi-threaded and that's why you don't see as much of a difference between these HEDT and desktop CPUs as in our more normal benchmarks.