Seriously ? hmm......... I would say this domain = registration cost. The reason is simple, alot users of Internet don't know much about new technologie. Your domain name is hard to remember and can make confusing for some. It's just my think. Maybe I'm wrong here.
It has a hyphen in it... a few numbers and is quite technical in nature and therefore only aimed towards a limited number of people. It is also a bit of a mouthful and doesn't look all that great written down.
I am certainly no domain expert at all, but looking at the above factors I would say it has little value unfortunately.
Actually I'm usually against the hyphen, but since the actually organization website is x86-64.com it could have some potential, maybe worth holding on to, lets see how well the opterons actually fair first. If the x86-64 platform takes off that could wind up being a pretty valuable domain.