Chrome OS 74 Performance: Understanding the Hyperthreading Impact on Your Chromebook

Experiencing slower Chromebook performance after the Chrome OS 74 update? You're not alone. This update intentionally disables CPU hyperthreading to address critical security vulnerabilities. Let's delve into what this means for your device and how it impacts your daily usage.

What are Microarchitectural Data Sampling (MDS) Vulnerabilities?

MDS vulnerabilities allow potential attackers to access sensitive data, including website content, passwords, credit card numbers, and cookies. These vulnerabilities could even be exploited to read host memory from virtual machines or privileged process memory from Android Apps.

To combat this, Chrome OS 74 disables CPU hyperthreading by default, protecting your data from these threats by limiting the avenues of attack.

How Does Disabling Hyperthreading Impact Chromebook Performance?

Hyperthreading allows a single CPU core to act as two virtual cores, improving performance by handling multiple tasks simultaneously. Disabling it can lead to a perceived slowdown, especially when multitasking or running demanding applications.

However, for typical Chromebook usage, which is "primarily interactive," Google suggests that the security benefits outweigh the performance cost with "no noticeable loss of responsiveness."

Is My Chromebook Affected by This Change?

This change primarily affects Chromebooks with Intel processors. If your Chromebook uses an ARM processor, it is not affected by these specific vulnerabilities.

It's important to note that these vulnerabilities aren't limited to Chromebooks; any device running on an Intel processor is potentially at risk. However, this is the best way Google found to handle open vulnerabilities.

Can I Re-enable Hyperthreading on My Chromebook?

While not recommended for security reasons, you can re-enable hyperthreading. Open Chrome and navigate to chrome://flags#scheduler-configuration and enable the “performance” setting. Understand the risks before making this change as it could expose your system to vulnerabilities.

Chrome OS 75: Further Mitigations are on the Horizon

Google plans to introduce additional mitigations in Chrome OS 75 to further address these vulnerabilities. This suggests ongoing commitment to security without sacrificing performance.

Final Thoughts: Balancing Security and Performance

Chrome OS 74's disabling of hyperthreading highlights the ongoing battle between security and performance. While you might notice a slight performance dip, the enhanced security posture is likely worth it for most users. Keep your Chromebook updated to receive the latest security patches and performance improvements.