I'm using an ATI Radeon HD 5970 Graphics card in my PC right now, the thing seems to work pretty much fine, games run alright, no errors, two GPUS show up in device manager, its on the most recent AMD driver, and crossfire is apparently enabled and working in GPU-Z.
Despite all of this, one GPU is almost never used. I can play Project Cars 2 which is both very graphically intensive and has excellent crossfire support, it will take one my GPUs to 100% usage and will rarely ever touch the other one at all, the other one only spikes above 0% maybe for a second during loading and that's it.
What might be wrong?