If you feel bored or adventurous, or both, or would just like to try the new Aura UI of Chromium (which will become default at some point), I encourage you to enable USE="aura" for www-client/chromium. Upstream still keeps it disabled by default, and that includes Google Chrome. In Gentoo it's easy to make a choice about this.
Aura is a new UI architecture which is GPU accelerated. You can read about the technical details in its documentation. Especially because of the use of hardware acceleration it'd be useful to get many people to test it. If these changes break in your configuration, you can know now (while it's still early in development process), report a bug (consider posting the bug link in the comments so I can ensure it gets proper attention), and get back to the working configuration.
Possible workaround for GPU problems is using --disable-gpu command-line flag. Note that this still means there is a bug that is unlikely to get fixed if you don't report it. It's also useful to include contents of about:gpu page in your bug report.
Finally, see the screenshots below for an idea how it looks like (click thumbnails to see original images):