Opera doesn't support WebGL/hardware acceleration so it's going to be slower. Well Opera 12 was released yesterday which has experimenatal hardware acceleration but you have to manually enable it.
http://my.opera.com/desktopteam/blog/2012/04/20/update-on-hardware-acceleration-in-opera-12
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"ECMAScript 5.1 for those who are too damn groovy for JavaScript.
Orientation Support
For Android only, support for camera use in the browser using the same, newer, getUserMedia syntax as Opera desktop Labs.
CSS3 radial gradients and the fabled -o-double-rainbow.
CORS (cross-origin resource sharing).
For Android only, hardware-accelerated WebGL for all things 3D and web. With WebGL on mobile,
it?ll be even easier to make games cross platform and distribute."
<img src="https://dl.dropbox.com/u/22173473/opera%20pics.png" border="0">