First review I see with two ARES cards in Crossfire! As expected, it's quite fast. I'm a bit disappointed, however, that they didn't include the GTX 480 in multi-GPU configuration. Agreed, the ARES is a SINGLE CARD, but running two GPUs is as impressive as one massive card. For 1 ARES, you can buy 2x GTX480 ... I think you can understand why I have mixed feelings about this.
Ok, you already know from our single card ARES review that running one card isn't reasonable for the average user. So what about two of them? Coming back to the car analogies: if you already have a Ferrari why would you buy a Bugatti Veyron? Probably simply because you can.
It's a bit similar with the ARES. Outside of extreme world-record seeking overclocking & benchmarking I can't imagine anyone who needs that much processing power. It should also be noted that many games won't gain that much with only a few exceptions. Mismatched combinations of the ARES with other HD 5000 Series cards do not seem to make much sense with the only exception being the HD 5870. Both ARES and HD 5870 share the same clock speeds which helps with CrossFire performance yields. Another interesting property of this combination is that it will work great in most motherboards. Running two ARES cards requires a spacing of two slots between the cards, with HD5870+ARES you can get away with a single slot spacing motherboard. Put the HD 5870 in the top slot and the ARES in the next available PCI-E slot. At "only" $1400 this is also cheaper and offers almost similar performance.
Running ARES CrossFire is not done by getting two of those cards. As mentioned before you will need a motherboard with enough spacing between the slots. Next you should have a fast monster CPU, our 3.8 GHz Core i7 is CPU limited in some benchmarks with dual ARES. So better look for something in the 4.5 GHz range. We already talked about monitors in the single card review, without a 2560x1600 30" display or an EyeFinity setup there is no need for the ARES. Finally, make sure you get a good power supply with loads of connectors. Our testing shows a maximum power draw per card of 450 W which means you should plan with 800 W for your CrossFire setup, add CPU and the rest of the system on top of that and 1200 W is a reasonable minimum to go for. The requirement of 4x PCI-E 8-pin and 2x PCI-E 6 pin power connectors is something not even all 1 kW+ power supplies provide, make sure to check on that while shopping.