Fire Alarms Systems

How good is this rare animal is a map?

If we look at the reference version of AMD's Radeon HD 6990, took over we have a board that were impressive on a number of fronts, if not all impressions were positive. The HD 6990 is based on two full Radeon HD 6970 GPUs on one board, each with its own 2 GB of frame buffer. In our first test, was the performance to be very fast, but the reference board was also quite loud under load.

So we waited a shipping board from one of the many AMD board partners to get, to formally verify a real product. And we waited. And waited some more. (Keep in mind that the availability of Nvidia's GTX 590 is not much better.)

At last, XFX shipped us an actual retail Radeon HD 6990, so we're finally able to render a verdict on AMD's killer card. Before we dive into benchmarks and observations, it's worth recapping the specs and features of the card, and its GPUs.

This card packs two HD 6970 GPUs, 4GB of fast GDDR5, and a noisy fan.

The Radeon HD 6990 has more than five total display terminals, even if it does not cut back on diversity as compared to the HD 6970, with four mini DisplayPort connectors and a single dual-link DVI port. XFX includes a pair of mini-DP to single-link DVI adapter (passive, active), plus a mini DP to HDMI adapter in the box. With two GPUs and GDDR5 4GB, this is a great card over 12 inches long. It also requires two 8-pin PCIe power connectors.

It is also worth looking at core clock speed differentials. Nvidia lowers the core clock speed of its dual-GPU graphics card GTX 590 by more than 20 percent from 772MHz to 607MHz. In contrast, AMD lowered the core clock speed of the HD 6990 GPUs only about 6 percent. It could be that AMD's GPUs, more power efficient, or just that AMD will be more aggressive about its overall design. Given the HD 6990 is equipped with a volume under load, we suspect a little of both.

As with the reference card has the XFX card, the overclocking mini-DIP switch that allows the clock frequency up to 880MHz, the same clock speed as a single-GPU HD 6970-card push. However, XFX is a giant yellow caution sticker on this switch. Since the rather somber warning, we tested the card in the default 830MHz clock frequency.

Now that we understand a bit more about the key features that we look at look at the performance.

AMD's HD 6990 wins seven of our benchmarks, ties into one, and loses to Nvidia's GTX 590 in the other three. 6990 is the maximum power is slightly lower. All the games we tested CrossFireX support, if you have an older game that are not supported AMD's dual-GPU technology, you will only see the power of a single HD-6970th However, AMD has done a lot of work with the drivers, and all current generation games, which we have used to get a solid performance boost.

On the other hand, the XFX HD 6990 is noisier at full throttle than the GTX 590th Apparently AMD has some work to do with its cooling solution to reduce noise. Or maybe AMD is pushing only the 40nm-based 6970-chips a little too hard, even at lower clock speeds. As you might suspect, given the fan noise, the HD 6990 gets pretty hot under full load, so you definitely want a sturdy case with air flow.

Bottom line: XFX is shipping the fastest graphics card, which you can buy, that is, if you find one. Availability is still very tight, and if you expect an order that it be ordered for several weeks. It's also pretty hot and pretty loud, so be aware that before buying. And all that performance comes at a price-HD-6990 is also the most expensive card you can get, at prices between $ 700 - $ 800 depending on the seller.

Still, if you are really looking for raw speed in a single graphics card, sound, heat, and price be damned, the HD 6990 is the front runner.

$ 700-800, www.xfxforce.com