The recent disclosure of another vulnerability in Intel processors, dubbed MDS (or Zombieload), has served as an impetus for another escalation of the debate about what kind of performance drop users who want to take advantage of the proposed fixes for hardware problems will have to put up with. Intel has published its own , which demonstrated a very small impact of fixes on performance even in the case of disabling Hyper-Threading technology. However, not everyone agrees with this position. The Phoronix website held its own independent problems in Linux, and found that the application of fixes for the entire complex of processor vulnerabilities identified recently leads to an average decrease in the performance of Intel processors by 16% without disabling Hyper-Threading and by 25% with it disabled. At the same time, the performance of AMD processors with Zen + architecture, as shown by the same tests, is reduced by only 3%.
From the tests presented in the study, we can conclude that the decrease in the performance of Intel processors is very different from application to application, and when Hyper-Threading is disabled, it can easily exceed even one and a half times the size. Actually, this is just about Apple, when naming its Zombieload elimination price, is up to 40%. At the same time, Apple, like Google, says that this is the only way to make systems based on Intel processors completely safe. If you do not resort to turning off Hyper-Threading, then the performance decrease can also be quite noticeable: in the worst case, it reaches a double size.
At the same time, it should be clarified that Phoronix tests concerned checking the impact of the entire set of patches against all recent vulnerabilities - Specter, Meltdown, L1TF and MDS. And this means that in this case we are talking about the maximum difference in performance that owners of Intel processors will receive after applying all the patches at once. This also explains the decrease in performance found in AMD processors. Although MDS does not apply to them, AMD chips are subject to some types of Specter vulnerabilities, which also require the installation of software patches. However, they do not need any drastic measures like disabling Hyper-Threading.
A serious deterioration in the performance of Intel processors after the application of patches can be a fatal factor for the company's position in the server market. While AMD is gearing up to raise the bar in performance with its new 7nm EPYC (Rome) processors, Intel chip performance is moving in the opposite direction. At the same time, it is impossible to refuse to fix vulnerabilities in server solutions - they represent the main danger there. Thus, AMD has a chance to soon become a supplier of faster server solutions, which will have a serious impact on its position in the server market, in which the company is going to win back a 10 percent share over the next year.
Users of desktop consumer-level systems may well refuse to apply patches, at least until potentially dangerous scenarios for exploiting vulnerabilities are identified. However, according to Phoronix benchmarks, while the Core i7-8700K is 7% faster than the Ryzen 2700 24X in its original state, on average, after patching, the advantage is reduced to 7%. If you follow the most conservative recommendations and, in addition, disable Hyper-Threading, then the older AMD processor will be 7% faster than the Core i8700-4K.
Source: 3dnews.ru