Power, Temperature and Noise
Adding a second card increases power consumption by less than 200W. We feel as if the power consumption would be closer to 500W if both Palit cards were running at the same core frequency and voltage as the single card.
Two high-performance cards in close proximity to one another doesn't play well for temps. You'd want them spaced out as much as possible on a motherboard; we used the two upper x16 PCIe slots that run from the CPU.
Two cards start off quiet but then, after gaming for a short period, the fans crank up to keep the GPUs cool. The end result is noticeable noise from the test-rig housed in a regular Corsair Graphite 600T chassis.
