[xubuntu] AMD-64 over i86-32?

I downloaded and bued the install disk for Xubuntu 15.10 Desktop AMD64, thinking to run it as a dual boot on my AMD 64 machine alongside the 15.10 desktop i86 version I run these days. However, on install it seems to give me the option to install over the i86-32 install, saving my files and all those programmes that are compatible with the 64-bit architecture. The machine is a Cybertronic tower about 6 years old, with an AMD Athlon X2 64 Dual Core 5000+ processor, a relatively new 1 TB hard drive, and 4G of RAM. Is this actually possible? Or should I dual-boot, transfer files and programmes, etc. (laborious)?

I seem to recall having asked a similar question a few years ago, but I can't find it offhand.