Speaking of CPU vulnerabilities, the Meltdown circuit breaker/Spectre ghost vulnerability discovered at the end of 2017 was impressive. More than 4 years have passed, and the ghosts hovering over the CPU have not dissipated, but have dealt everyone a heavy blow.
Spectre Spectre took advantage of a vulnerability in the CPU's branch prediction mechanism, and although previous mitigations have been as far as possible to defend against attacks against this vulnerability, the VUSEC systems and cybersecurity research team from Amsterdam discovered a new vulnerability last week that bypassed the mitigation through the branch history buffer, which we will call a new variant of the spectre.
VUSec verified the vulnerability on Intel and Arm CPUs, and AMD was deemed unaffected. But three security researchers at Intel were quick to point out that AMD also had security implications, and that existing LFENCE mitigations were insufficient to defend against attacks from Spectre V2, and AMD subsequently confirmed this. Ryzen doesn't need a new patch, but rather a tweak of mitigation: from LFENCE to a generic Retopoline. At this point, Intel, AMD, and Arm will all have to sacrifice performance again in exchange for security.
As a player, of course, the biggest concern is how much the patch of the new vulnerability will affect performance. Linux reacts faster than Windows, so this time we'll look at the results of Phronix's test on Linux. It should be noted that the test items for each of the following CPUs are not consistent, and the test for AMD includes the Stress-NG context switching test, which directly reflects the maximum performance loss that the patch can bring under extreme conditions.
For the Ryzen™ 9 5950X, stress-NG context switching scores saw the highest drop of 54%. The mobile Ryzen™ 9 5900HS also reached 22%.
The performance impact of the Stress-NG context switching test is thrilling, but the actual application is different from the roaster, taking the fio storage performance test that appears in amD and Intel testing as an example, which is also the most significant manifestation of the impact of a ghost vulnerability, and is closer to the use of ordinary PC users than network performance testing and database testing.
After the Intel Core i9-12900K enabled the new patch, the 4K random read performance was attenuated by 4.2%, and the 4K random write performance was attenuated by 14.5%. The previous-generation notebook CPU Core i7-1185G7 was hit harder: 4K random write performance attenuated by 34.1% (4K random read performance was not tested).
AmD Ryzen™ 9 5950X attenuated 5% of 4K random write performance after enabling the new patch (4K random read performance was not tested).
Notebook CPU Ryzen™ 9 5900HS enabled the new patch, 4K random read performance attenuation of 3.6% to 5.4%, 4K random write performance decay of 5.7%.
In the SSD test, the 4K random read and write performance of the Intel platform has always been higher than that of the AMD platform, but the attenuation of Intel after the patch is also larger.
Microsoft's vulnerability patch for Windows systems should also be pushed in the near future. The good news is that gaming performance is not expected to be significantly affected.