Apple’s ZombieLoad fix hits Mac performance by up to 40 per cent


Apple's ZombieLoad fix hits Mac performance by up to 40 per cent

FIXING THE ‘ZOMBIELOAD’ FLAWS discovered in Intel’s CPUs could see performance of some Apple Mac machines tanking by up to 40 per cent.

The recently-uncovered Microarchitectural Data Sampling (MDS) exploits found in Intel’s Core processors dating back as far as 2008 have to lead to Apple, like Google, recommending that customers disable the CPUs’ Hyperthreading feature.

But when Apple put this to the test using public benchmarks and tests on multi-threaded workloads – think video encoding, for example – it found that a significant drop in processor performance could occur.

Apple being Apple didn’t say what type of Mac would suffer such a performance drop, but we’d hazard a guess and say it’s probably one of the firm’s machines with a powerful multi-core processor rather than the dual-core-equipped MacBook Air.

Nevertheless, the performance drop will affect other Mac machines that have been using Hyperthreading up to this point, though by how much will have to be assessed on a case by case basis.

With that in mind, it’s perhaps worth noting that the MDS vulnerabilities have only been exploited under test conditions and for a lot of individual PC users probably don’t pose too much of a direct risk.

“Although there are no known exploits affecting customers at the time of this writing, customers with computers at heightened risk or who run untrusted software on their Mac can optionally enable full mitigation to prevent harmful apps from exploiting these vulnerabilities,” said Apple.

“Full mitigation requires using the Terminal app to enable an additional CPU instruction and disable hyper-threading processing technology.”

In this case, the onus on how much one wants the vulnerabilities to be mitigated rests on the user, rather than Apple’s shoulders.

But the whole shebang does highlight how the speculative execution hardware-level vulnerabilities in Intel’s chips aren’t likely to go away anytime soon, and that the spectre of Spectre has yet to be exorcised.