Overclocking
Two Radeon R9 295Xs are overkill for most systems, but better results can be obtained by adding a higher power target and increasing both core and memory by a small margin. We settled on a final, stable speed of 1,061MHz core and 5,380MHz memory.
Four overclocked Hawaii GPUs take top spot. Giving Nvidia the bragging rights for now, the also-overclocked WaterForce is faster at all settings.
Overclocked performance is a product of how good the baseline score is. There's no way, with present drivers, the quad-GPU R9 295X2 can mount a serious challenge to the three-way GeForce GTX 980 in Total War: Rome II.