AMD ATI Radeon HD6450 1GB in Mac Pro?

Hey, I have a Mac Pro 1.1 and want to install a new video card. I Have a small budget of around $100. I don't need anything fancy or new. I have found a AMD ATI Radeon HD6450 1GB for $40, would it work in my Mac? I Understand with some cards that the boot screen won't show up on the Mac, but will it function other than that?

Does anyone know? Thanks heaps