Testing shows AMD Zen 4 handling Spectre, Retbleed mitigations like a real champ

At the end of August, AMD unveiled its Ryzen 7000 series desktop CPU lineup based on the Zen 4 micro-architecture. And although the excitement around it has been somewhat muddled down by Intel's 13th Gen Raptor Lake-S lineup which has come out guns blazing with lower prices, it does look like Zen 4 also has some redeeming qualities that enthusiasts would be keen to consider.

Fellow media outlet Phoronix decided to test the new Ryzen 9 7950X, which is the flagship Ryzen 7000 SKU, with the various CPU vulnerability mitigations and more turned on and off. And the results are somewhat surprising in a good way for AMD.

In the default state where the mitigations are enabled, the new Zen 4 chip actually manages to win by a bigger overall margin than with the mitigations disabled. Phoronix says:

With Zen 4 you can still boot the kernel with mitigations=off to disable the SSB, Spectre V1, and Spectre V2 mitigations applied while leaving the system in a "vulnerable" state. While many route to the mitigations=off approach to avoid the performance penalties attributed to the different mitigations, in the case of AMD Zen 4 on the Ryzen 9 7950X it's not actually beneficial.

Here is a full breakdown of the all tests showing the performance advantage of the two scenarios:

Here is the geometric mean of the results where the default (mitigations enabled) state has clearly won more. Out of the total 190 tests conducted in this evaluation, the default state managed to win nearly 72% of the tests.

Overall, it looks like AMD has clearly built on top of what it had achieved with Zen 3. The previously tested 5950X had actually managed to fare better than tested Intel CPUs with the retpoline patch.

Source and images: Phoronix

Testing shows AMD Zen 4 handling Spectre, Retbleed mitigations like a real champ