Over the last few months a potential exploit has come to light which is very similar to the Spectre and Meltdown worries of last year.
ChromeOS is an extremely secure Operating System, built on top of Linux by Google. At some point over the last few months they decided to implement some of these patches and disable something called Hyper-Threading. Hyper-Threading is a means that the CPU uses to process multiple tasks at the same time. The threat is basically that sensitive values could leak through Hyper-Threading – enabling a rogue bit of code to read data in another thread.
Intel believes that turning off Hyper-Threading is a heavy-handed approach to dealing with this issue, as performance could drop by 30-40%. OsX has left it up to the user to disable it – while Google believes that it’s up to the user to re-enable it.
Obviously you’ll need to decide if you’re manipulating extremely sensitive data – but I think ChromeOS is secure enough without the worry of rogue code being launched which can read potential data being processed at exactly the same time. Turning it back on sped my Pixel Slate up noticeably.
Instructions to turn it on and off can be found here. It only affects Intel-Based Chromebooks.