Firefox's performance settings

To give you the fastest and most reliable experience, Firefox automatically uses settings that work best with your computer. You can always change these settings in your Firefox Settings by unchecking the box next to Use recommended performance settings and changing the following:

• Use hardware acceleration when available: This allows Firefox to use your graphics card (if available) instead of your computer’s main software to display graphics-heavy applications, like videos or web games. This frees up resources on your computer so it can run other applications, like Firefox, faster.
• Set maximum content processes: Firefox can run each tab separately so each one performs better. However, having too many tabs can slow down your computer, and consequently, Firefox. The recommended maximum is four, but you can set up to seven.