How can I install a 64-bit OS on a 2006 Mac Pro with 32-bit EFI? I have a Mac Pro 2006 that has 64-bit processors, yet only boots 32-bit operating systems (aside from OSX). Is there a way I can install 64-bit Ubuntu Server, or any 64-bit OS for that matter, on this Mac? I'm getting tired of Snow Leopard Server.

EDIT: Uhm, computer is silver and looks like a cheese grater. It's a Mac Pro 2006 (first gen) with a single 250 GB HDD (original), 2 GB DDR2, and 2 dual-core Xeons.
There are instructions online that tell you how to replace the 32-bit EFI with a 64-bit version. Obviously this comes with certain risks and certain issues. Worth pointing out that I haven't tried this myself.

http://lowendmac.com/2014/modernizing-the-mac-pro-11-and-21/

If you want to install 64-bit versions of Linux there are a number of resources online that explain how to accomplish this. For example the following page has links to Linux install images that have been specifically modified to allow installation on 64-bit Macs with 32-bit EFI.

https://mattgadient.com/2016/07/11/linux-dvd-images-and-how-to-for-32-bit-efi-macs-late-2006-models/