Try some of the following tips:
- Reduce the amount of animated elements, for example use a fixed caption style or just the fade effect.
- Disable the Overlay or the Special effects.
- Turn off the animation by setting General tab > Animation speed to 0. You can keep the overlay and special effects this way, but the transition will be instant.
- Decrease the General tab > Target row height value.
- If you have lots of small thumbnails, disable the captions as they get too small. This helps reduce animated elements.
- Try restarting your browser as it might be suffering due to the amount of tabs you opened during its run, consuming too much memory.
- Close Flash or HD videos playing in the background.
- Close any browser debugger tools because they slow animations when opened.
If your concern is primarily mobile devices, even up to a point where they might crash, then also check out The browser crashes or closes on my older iPhone or iPad.