What's a GPU war without two powerful rivals battling it out over who wears the flagship card crown? AMD struck first with 'Antilles', a dual GPU solution better known as the HD 6990. This particular piece of kit comes in at a hefty price with similarly exuberant power requirements and heat/noise output. Meanwhile, Nvidia had its own plans underway in the form of a dual Fermi (GF110 core, naturally) card that boasts 3GB of GDDR5 memory (1.5GB per core). Essentially, it's two GTX580s shoved together with their clock rates tamed to ensure that temperature and power requirements stay somewhat sane. By sane, we mean a Thermal Design Power (TDP) of 365W, so perhaps that line was crossed a while back.
ASUS's take on the GTX590 comes equipped with all the peripherals you'd expect it to – a dual 6-pin to 8-pin cable, a DVI to VGA adapter, and a DVI to HDMI adapter. These compliment the inclusion of three dual-link DVI-I ports, and a single mini DisplayPort. No portion of the I/O plate is left unattended; any given area either houses a port, or has a hole cut into it to allow hot air to flow through.
And boy does that hot air flow! Nvidia has learnt that loud cards are unpleasant cards, which may explain why the cooling solution on the reference design ASUS card is very conservative. Under 100 per cent load, the fans refused to budge from 40 per cent, maintaining a surprisingly reasonable 78c. However, the shroud is sealed well around the card, so placing your hand on or near the vent is met with very warm results. Oh, and perhaps we should mention that this card reeks of burning, well, something under load – not quite the infamous 'magic smoke' smell, but it can't be healthy.
Perhaps it's just us, but a hot dual-core card with a massive TDP and an air cooler just begs to be overclocked. Afterburner decided that we were not entitled to voltage adjustments, nor did ASUS's own SmartDoctor, so we were stuck with the stock 0.938v. So much for cooking with gas, but not to worry, we channeled the spirit of MacGyver and made do with what we had. Our result after much fiddling (it turns out that Furmark isn't the best indicator of stability due to throttling and stress of only a single GPU) was 690Mhz on the core, 1380Mhz on the shaders, and 885MHz on the memory. Not too shabby.
Benchmarks followed, which saw an intriguing result in Crysis. While the average and maximum FPS increased by about three, the minimum dropped by this same amount. Fortunately our other tests were free of such discrepancies. Lost Planet 2 gained 13 FPS, Unigine Heaven's extreme tessellation setting saw a 4.5 FPS increase, while the no tessellation test was boosted by 8 FPS. Last but not least, 3DMark11's performance run raised 834 points, and 'extreme' 267 points. Overall, this card performs brilliantly.
It's worth noting that the noise level of the card during benchmarking didn't exceed 58dB, and that's after being overclocked! Stress testing did push it to 61dB with a maximum temperature of 81c. Quite impressive, but we're not so sure that the second core was doing much.
If it came down to choosing between the HD6990 and the GTX590, and both were priced equally (which they aren't, the GTX 590's tend to come at a $150 premium), we'd go for the latter – purely because it's so amazingly quiet. However, $150 is a lot of money to part with, especially when the total cost scrapes under a cool $1000. One will always purchase a dual-core card at a significant cost, but which is more valuable, the comfort of a quiet machine, or a fatter wallet?
If you're looking for multi-card performance in a small package, and price is no object, then this may very well be the best path to go down. Otherwise, consider the HD 6990, or grab a high end single core card such as the GTX 580 or the HD 6970.