Noise, Heat, & Power Consumption
We used SeaSonic's Power Angel Power Meter to measure the amount of power our test system pulled from the wall. You'll find three figures below: power supply's maximum rated wattage, peak power consumption under a full CPU/GPU load, and how much the system pulled from the wall when idle (following a fresh system boot).
Dell requires an upgrade to an 875W power supply (up from the default 525W) for certain videocard selections, including dual Radeon HD 6950 cards. That's a wise move on Dell's part, as we measured a peak load of 594W when stressing the Aurora R3 with Prime95 and Furmark (it takes some .exe renaming trickery to get Furmark to fully tax multiple GPUs, and it's not entirely safe to do so, but hey, HH readers are worth it). That 875W power supply gives you a fair amount of headroom for future upgrades.
Heat and Acoustics
Alienware's Aurora R3 runs hot, to the point where it hurts your hand to touch the graphics card under load. You shouldn't be fondling the components when they're running anyway, but the point here is the hardware selection asks a lot from the cooling system. To battle thermals, Alienware equips the processor with a liquid cooler and lets the videocards expel hot air out the back of the case. The airflow scheme keeps instability from rearing its unwanted head, but at another cost: Noise.
The Aurora R3 isn't a suitable vehicle for abductions because it stands zero chance of sneaking up on anyone. Its liquid cooling system isn't extended to the graphics cards, and things get loud in a hurry while gaming. Day-to-day computing isn't affected, but fire up a taxing game and the GPU cooling fans kick on and spin up considerably. At it's worst, you'll need a good set of speakers or headphones to drown out the noise the Aurora R3 puts out. That said, this isn't all that uncommon for high-end graphics setups like this.
In addition, and to our surprise, at one point when the fan speeds jumped up a level, one of them developed an annoying clicking sound, perhaps due to a faulty bearing.