I took the plunge earlier this week and installed Jaunty (Ubuntu 9.04 beta) x64 clean on ext4 alongside my 8.10 install.
All in all very impressive, however I came across a bug with Flash/Java that caused a crash report. I used the opportunity to report the bug and found the 2 bug reports bug #178038 & #158126 when I signed in.
Over the past few days I've received a few emails from those subscriptions pointing to a fix. Most notable is that finally both Sun and Adobe have come around to officially releasing 64-bit versions of their Flash & Java platforms.
There was a very useful post about how to go about the Java install here. However it's in German. Babelfish translation here.
Let's start with Sun Java, I downloaded the appropriate JRE 64-bit package from this link.
A quick Google of the terms "./jre-6u13-linux-x64.bin jaunty" revealed this post which appears to work great, however the 2nd test page listed does cause my firefox to close unexpectedly and immediately.
Now for x64 Flash, found this HOWTO on the same site. Very simple install and all looks good since installing it.
One thing I did have to change was Firefox, when I did an About:plugins - I have 3 flash plugins listed.
I clicked on Tools, manage Content Plugins and changed the plugins to point to the new plugin.
Wham! everything got a lot quicker!
One thing I had noticed before this change was that the login page at www.ogame.org and www.ogame.us when both open at the same time would chew up to 50% cpu before. Now it's practically idle and the page load is much quicker.
Youtube loaded fast and was very slick.