No need to be sorry. Those GPUs are two Radeon HD 5870 in Crossfire. They are pretty old but surprisingly capable. 1GB VRAM is sometimes an issue but your game works fine with 1GB. CPU is a Phenom II X4 965. No problems on the CPU side though.
Thanks for the tip with for the resolution I'll try it at native res on my CRT when I get the time. The scaling of my LCD is pretty bad for sharp pixels.
I thought the 2D sprite renderer in Unity was pretty light weight. I only did a tiny project though. It might just be a setting somewhere that eats the performance.
Songs of Conquest for example runs great on a single GPU.
Are you using a Sprite Atlas? It helps immensely with reducing draw calls.
I actually don't remember my score. Now I have a reason to go through it again ;)