AMD Ryzen CPU vulnerability fix can cause massive performance loss

AMD Inception mitigations can cause CPU performance degradation of up to 54%, but most consumers don't need to worry, according to Phoronix's testing.

AMD Ryzen CPU Inception vulnerability Phoronix testing: AMD Ryzen CPUs appear next to a red button reading 'help' against an orange background.

AMD has recently declared that a concerning vulnerability, known as ‘Inception’, is affecting its Ryzen CPUs. Until now, we weren’t sure exactly how Inception might impact your gaming PC. But thanks to testing conducted by open source news site, Phoronix, we’ve got an idea of the performance degradation AMD Inception mitigations could cause, and it’s not pretty.


Researchers at ETH Zurich, a Swiss University, discovered Inception early last week by combining two known attacks called ‘Training in Transient Execution’ and ‘Phantom speculation’ to devise the formidable ‘Inception’ attack. If it sounds complicated, that’s because it is.

Inception confuses your processor by forcing it to repeat the same function over and over, a scenario that can leave your PC vulnerable to substantial data leaks. Inception can theoretically affect all Zen CPUs, in a worrying situation for those of us rocking team red processors.

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Although AMD has not yet released an official solution, it has issued mitigated microcode for ‘Family 19h’ processors. Phoronix conducted benchmark tests using this microcode on an AMD EPYC 7763 processor to test the possible effects of Inception.

The first key finding, thankfully, is that the new mitigations have negligible impact on user applications. What a relief! 7zip compression experienced the most significant performance decline at around 13%. That means if you’re using your PC for everyday tasks like gaming, using Microsoft Office, or browsing the web, you probably don’t need to worry. However, Phoronix noted more significant performance decreases of over 50% in resource-intensive applications like MariaDB.

Realistically, new hardware vulnerabilities are always going to be uncovered, and companies usually take them pretty seriously and mitigate their impact on consumers. It seems unlikely that you need to worry too much about Inception, unless you’re engaging in heavy data processing tasks with your PC. Assuming this hasn’t put you off AMD processors, and there’s no reason why it should, check out our best gaming CPU list to make sure your rig is kitted out with the best hardware.