Opera Team has released a new alpha version of their upcoming Opera 12 aka Wahoo, many stability and security fixes were made in this version.
This new snapshot includes the first look at the DirectX backend. Most users on Vista and Windows 7 will by default use this backend instead of the OpenGL backend for performance and stability reasons, but be aware that currently WebGL support using the OpenGL backend is more complete than when using DirectX.
You can also enable WebGL and hardware acceleration. You can enable these features by setting both opera:config#UserPrefs|EnableHardwareAcceleration and opera:config#UserPrefs|EnableWebGL to 1, then saving and restarting Opera.