Migrating from OpenSuSE Server to Ubuntu Server, tons of questions

I have a 64BIT OpenSuSE server I'm looking to migrate over to Ubuntu.
Dell 7500 Workstation with Intel E5 Xeon processor
64GB of RAM and 20TB of data
MySQL database to migrate over with it.

First off before going any further, I noticed the only architecture for 64bit is AMD 64, so does this mean having a Dell server based on Intel, I'm dead in the water as is? If so I can just go towards SME Server, but I would rather try Ubuntu as it's a bit unique on it's own/to try something different.

Or is there something unique about the 32bit version that will allow it to use the full 64GB of RAM? This is a domain controller that will also virtualize multiple other servers and other functions. Basically a server with multiple Virtual servers that will at least host 15 VMs total using VirtualBox. So no room for games on it.