Asus' Radeon HD 7970 DirectCU II TOP
We'll start with Asus' Radeon HD 7970 DirectCU II TOP because, well, it's the biggest. This monster is 5.1" tall, 2.1" thick and occupies three expansion slots. The card's 11" length is about average, making the DirectCU a rather stout offering. Behold, the Henry Rollins of graphics cards:
Maybe the racing stripes are more befitting of a muscle car, but I've exceeded my allotment of automotive analogies for probably all of eternity. The DirectCU simply looks badass. A lot of that is due to the mass of metal sitting under the matte-black cooling shroud.
Beneath the blades of one of the dual cooling fans, we see an intricate network of six copper heatpipes. The plumbing feeds into a pair of finned radiators that wouldn't look out of place atop a desktop CPU. Baby's got back, too. Check out the brushed metal plate affixed to the back side of the card:
The screwed-on panel is riddled with ventilation holes to prevent hot air from accumulating. These holes are hexagonal, nicely complementing the angular lines of the rest of the cooler.
All this additional cooling hints at higher clock speeds, and Asus delivers. The core clock speed of the DirectCU's Tahiti GPU has been raised from its default 925MHz to an even 1GHz. That speed matches the Radeon HD 7970 GHz Edition, but the Asus card lacks AMD's new opportunistic clock-boosting mojo. The DirectCU's 3GB of GDDR5 memory operates at 5.6 GT/s, a little slower than the 7970 GHz Edition's 6 GT/s memory.
Of course, those speeds aren't written in stone. The DirectCU is geared toward overclockers, and its top edge features solder points for hard9core tweakers who want to monitor and control onboard voltages precisely. The card can draw more power than typical Radeons, too. It has dual 8-pin PCIe power connectors, an upgrade over the 6+8 config found on standard flavors of the 7970. Fancy power regulation components abound, and Asus even includes an auxiliary heatsink that should be slapped onto the MOSFETs when the card is cooled with liquid nitrogen.
The DirectCU also has quite a collection of display ports. And DisplayPort ports. Mmmm... ports.
Radeon HD 7970 cards usually offer dual Mini DisplayPort outputs alongside single DVI and HDMI connectors. The DirectCU has two DVI ports and four full-sized DisplayPort outs, enough connectivity for a six-screen Eyefinity wall. There are a couple of caveats, though. The included HDMI adapter works only with the right DVI port. Also, the left DVI output offers a dual-link connection only when the left-most DisplayPort output is disabled. A switch near the CrossFire connectors flips between the output configurations.
Running a three-screen setup on the DirectCU requires the use of at least one DisplayPort connector. Unless you have a compatible monitor, you'll need an active DisplayPort adapter, which runs about $25 on Newegg. The DisplayPort requirement isn't unique to the Asus card. All Radeons are afflicted with this limitation except for a handful of custom Sapphire models that integrate active DisplayPort adapters onto their circuit boards.
Our LCDs have DisplayPort inputs, so we didn't have to bother with active adapters. Since we didn't want to make things easy for the cards, we used a mix of connectors: one DisplayPort, one DVI, and one HDMI with the adapter included in the box. The setup process was a breeze.
Once the displays are positioned and the standard Catalyst drivers are installed, putting together an Eyefinity array takes all of a couple minutes in the control panel setup wizard. The user is presented with a few configuration options, including the 3x1 setup we prefer. Once the basic layout is set, the next step ascertains the position of each screen and delivers an ultra-wide desktop. Ours measured 5760x1200 pixels to start.
We then applied bezel correction, which AMD's drivers pretty much nailed automatically before we did a little fine-tuning. This feature extends Eyefinity's virtual display beneath the bezels, creating the illusion that they're merely bars blocking your view of the world. Without bezel correction, the images produced by multi-screen setups are distorted; the scene stops at the bezel border and continues on the other side as if there's been no interruption. AMD's bezel-correction interface is easy to use, and it left us with a 6084x1200 desktop.
The final step is deciding whether to have the Windows taskbar span all three screens or just sit on one of them. Ideally, the spanning option would intelligently groups one's taskbar items on each display. Instead, it puts the Start button all the way over on the left and proceed from there, which isn't terribly convenient. You're probably better off with a single-screen taskbar centered in the middle. (Incidentally, the stretched taskbar's flaws extend to Nvidia Surround setups, too. Blame Microsoft.)
That's AMD's hat in the ring. Let's see what Nvidia has to offer.