The recently discovered hardware-level security flaws have begun to impact CPU performance. Moreover, it appears that CPUs made by Intel suffer much more than AMD.
In the battle against CPU-level security vulnerabilities, Intel began developing and issuing patches to mitigate the risk. The most impacted computer systems were those running unsupported Windows Operating Systems like Windows XP, Windows 2003 Server, etc. While large companies like Microsoft, Google, Apple, and Intel are fighting to minimize the impact of the bug, the fallout of the same is diminished CPU performance.
Intel’s 2011 and later CPUs are vulnerable to ZombieLoad. The company recently released microcode to patch vulnerable processors, including Intel Xeon, Intel Broadwell, Sandy Bridge, Skylake and Haswell chips. As expected, the patches bring down the CPU performance. In essence, the patches sacrifice performance for security. Intel’s own internal benchmarking previously indicated the negative impact on performance would be well below 10 percent. However, it appears real-world impact is much more.
Phoronix, a publication that focuses on Linux-related news and reviews, conducted its own testing. The platform claims the patches Intel released, reduce the performance of its CPUs by about 16 percent on an average. Incidentally, this loss is with Intel’s proprietary Hyper-Threading enabled. With Hyper-Threading disabled, the losses scale up significantly.
Competing against Intel’s Hyper-Threading is AMD’s Simultaneous Multi-Threading (SMT). Incidentally, AMD processors too, lose some performance with mitigations enabled. This is because AMD is vulnerable to some Spectre variants. But Phoronix categorically noted that AMD processors do not have any known security faults when SMT is enabled. Hence, the overall negative impact is around 3 percent on average.
Phoronix derived these percentages by taking into consideration the geometric mean of test results. In other words, there could be some variance in the impact of the security patches in the performance of individual processors. However, the impact is certainly quite higher than what Intel had earlier claimed. Moreover, the overhead of the mitigations significantly reduces the real-world performance gap between Intel and AMD’s processors. According to the platform, the patches bring the Intel Core i7 8700K CPUs closer to the Ryzen 7 2700X and the Core i9 7980XE to the Threadripper 2990WX.
AMD has been aggressively ramping up the performance of its processors to take on Intel. The company recently announced its next-generation processors will be fabricated on the 7nm manufacturing process. Could desktop and server users soon have a much better alternative to Intel CPUs owing to the lesser risks faced by AMD processors?