Google Disables Intel Hyperthreading on ChromeOS

But, with Hyper-Threading enabled, users could execute code, such as by visiting a website or running an Android app, that exploits MDS to read sensitive memory contents. Users and customers who process particularly sensitive data on their Chrome OS devices are nonetheless advised to disable Hyper-Threading as a measure of caution. However, uncacheable memory does still move through the store buffers, fill buffers, and load ports;allowing data stored in UC regions to still be leaked via the mechanisms described above.

Source: sites.google.com