The single card, dual-graphics idea isn’t new. AMD has been doing it for almost 5 years now, and Nvidia too has come out with some incredible examples of this concept. Recent examples from both AMD and Nvidia, the HD 6990 and GTX 590 respectively, gave incredible powerhouse performance, but at the cost of insane power draw and fan noise.
Almost a year ago Nvidia released their GTX 690, based on dual GTX 680 cards, and although 3rd party manufacturers like ASUS and PowerColor came up with their own solutions to the HD 7990, today AMD finally released their true behemoth, the HD 7990 officially.
In essence, the HD 7990 is one card with two HD 7970s strapped on one PCB, yet amazingly the dimensions are the same as the current HD 7970 GHz Edition model pushing 12-inches in length. Basically you’re using up just two slots on your motherboard where normally you’d have to give up four slots, if not six, depending on the heatsink provided by the manufacturer.
The price tag of $999 is, therefore, justified in that you’d end up paying about the same for two HD 7970s while also giving up more than double the space on your motherboard. But that’s not even the best part! AMD has decided to bring over their Never Settle bundles to the HD 7990 as well, but instead of retailers emailing you the code, everything you need to claim your eight free games is packed in the box. Yes, every HD 7990 comes with eight free games. Far Cry 3, Far Cry 3 Blood Dragon, Crysis 3, Bioshock Infinite, Tomb Raider, Hitman Absolution, Sleeping Dogs and Deus Ex: Human Revolution. Buying these eight games on Steam and Origin right now will cost you $325; so the HD 7990 costs $674, not bad at all for two HD 7970s.
Now the HD 7990 has a very pleasing design, both aesthetically and practically. The entire PCB is covered end to end with aluminum fins, each of the two blocks directly taking in four copper heat pipes from the GPUs. Stacked on top are three 85mm fans with the cover letting air out from all four sides. This open-ended heatsink means that your case needs to have proper airflow, lest the heat coming off from the HD 7990 starts to overheat the rest of your components. The package is completed with a huge metal backplate that keeps things cool from all sides.
Inside the two HD 7970 Tahiti chips are joined by a PLX PCIe 3.0 chipset for CrossFire, while being surrounded by 6GB GDDR5 or memory. There’s also a small BIOS switch on the top which basically allows you switch to a backup BIOS in case your overclocking efforts were too enthusiastic for the card to handle. Otherwise there are two 8-pin connectors to power the HD 7990, with the ability to give you a 5x Eyefinity display setup afforded by the four DisplayPorts and DVI port on the back.
The below testbed was used to benchmark the HD 7990 along with the supplied Catalyst press drivers.
And these were the settings used for the tests performed:
During our tests the HD 7970 idled at 40 °C, maxing out at 79 °C during all of our benchmarks. That’s a remarkably cool card considering the amount of power those two Tahiti chips are burning through. Again, kudos to AMD for making the power consumption so efficient that it shows. I’m guessing, however, that unlike our open testbed, an HD 7990 inside a case may go as high as 85 °C. Your mileage may vary depending on the amount of cooling and airflow your case has.
The sound was loud, but nothing annoying. Inside a case it won’t be so noticeable given the open-air design of the heatsink, so you’re going the avoid the hair-dryer sound form the previous generation HD 5990 and HD 6990 cards.
Ultimately the HD 7990 is an excellent card in its own right, although coming a year after the GTX 690 at the same price, and without a lower price may hurt it. Still, the eight games bundled in is an incredible offer, but I’m inclined to think that most people who’d be able to afford a card like this must have already played some, if not most of these games. The timing is surely late for the HD 7990 as the HD 8000 series is on the horizon, but then again massive sales isn’t what AMD is banking on with their latest flagship card.