I did a single Octane run on each for my own amusement. Totally unscientific methodology but the results are good enough for me. Chromium is v. 27.0.1424.0 rev 184630 (probably the latest build) from a zipfile (Google makes it practically impossible to download zips of anything else).
IE still has to do a lot to catch up and the Windows 7 desktop version's GUI is same old IE9 without any changes.
[1] http://arewefastyet.com/