migrating architectures?????

[Vizion]

Has anyone successfully upgraded from  working i386 freebsd system by moving to a amd64 architecture?

I had a few pessimistic replies on the freebsd-questions list to my original posting (see below) and felt that I should at least enquire on this list to see whether I have no option but to reinstall. 

Original posting to Freebsd-questions:
------------------------------------
> I have a freebsd Generic System 6.0-RELEASE #0 compiled Thursday Nov 3 2005
> originally on an Abit VA-20 motherboard equipped with an AMD sempron cpu in
> its 462 socket.
>
> The Abit motherboard died due to a chip failure and I did not feel like
> taking a risk using of the same thing happening again.
>
> I purchased a Gigabyte GA-K8N51GMF-9 and installed an AMD Athlon 64 3200+
> processor in the socket 939 and transferred the hardware to it.
>
> Apart from not yet getting X-windows to work I am pleased to report that
> system seems to be functioning well.(I have not yet worked out how to
> change the X config to support the nVIDIA GeForce 6100 chipset).
>
> I now want to upgrade the system to FreeBSD 6.1-RELEASE-AMD64 and
> downloaded the appropriate iso images onto cd.
.