As games such as Doom 3 push PC hardware to its limits, gamers are looking to PCI Express cards to maximize performance. We investigated the best upgrade options.

For the first time in years, 3D games have jumped ahead of the hardware that runs them – specifically, high-end graphics boards. You no longer have to worry that you'll spend a stack of cash on the latest graphics board only to wait months before a game can challenge it. Games such as Doom 3 and Far Cry are here now, and they’re challenging, to both you and your graphics board.

Another complication has arisen, too. Boards with the PCI Express interface have become available, with twice the bandwidth of the 8X AGP interface. This raises some questions: Is PCI Express required for top performance? Is it time to upgrade your computer along with your graphics?

We put 17 boards – nine AGP and eight PCI Express – through the rigors of cutting-edge game graphics.

AGP versus PCI Express

Our test results suggest that there's no immediate reason to dump your AGP motherboard solely to boost graphics performance. Today's graphics boards don’t take full advantage of the 8X AGP bus, so the AGP-interface versions of high-end boards can give you their best. Your graphics card’s speed and your PC’s CPU still mostly determine gaming performance.

On the other hand, a new PCI Express motherboard provides both greater potential performance and a hedge against obsolescence. Many people who need to replace their aging PCs will find it worthwhile to opt for a PCI Express graphics board/motherboard combination.

We can’t directly compare the frame rates of AGP boards with those of their PCI Express counterparts – even where the graphics chip set and memory specifications are the same. This is because we were unable to set up matching test beds with dual PCI Express and AGP support. At press time, no motherboards offered dual AGP/PCI Express support, and few are likely to do so in the near future.

Power graphics

In a very close race, and in a field of boards dominated by NVidia GeForce 6800 series and ATI Radeon X800 graphics processors, the top performer in the AGP category was EVGA.com's E-GeForce 6800 Ultra. The only board we tested that came with NVidia's GeForce 6800 Ultra graphics processor, it produced the fastest frame rates in five of our seven gaming tests. However, the software bundle was weak, and support is also limited. EVGA do not ship to the UK at this time.

After the EVGA we saw a virtual tie in performance among five other cards from ATI, BFG Tech, MSI, PNY, and PowerColor – all using either ATI's Radeon X800 XT chip or NVidia's GeForce 6800 GT (which has a lower clock speed than the 6800 Ultra). The MSI NX6800GT shone though, thanks to a stellar software bundle.

Performance results were even closer among the top four PCI Express boards. The one board in the PCI Express category that was powered by NVidia's GeForce 6800 GT – PNY's Verto 6800GT PCI Express – was our top performer, though by only a small margin. There was little difference between the frame rate of the next three cards – from Asus Computer International, ATI, and PowerColor, all using ATI's Radeon X800 XT.

Running games – especially complex ones like Doom 3 and Far Cry – at a high, 1,600-x-1,200-pixel resolution and turning on advanced graphics settings such as antialiasing and anisotropic filtering exacts a toll on frame rates. When it ran Doom 3, the EVGA E-GeForce 6800 Ultra, for example, dropped from an average of 60 frames per second at 1,024-x-768 resolution to 49fps at 1,600-x-1,200. Adding antialiasing at the higher resolution dropped it down to a mere 32fps. For the most part, the slower the board, the greater the frame rate loss.

Ports

Aside from performance, these boards differ in the ports they offer. All have at least one DVI port and support for a 15-pin VGA connection and two displays. A few boards – the Asus Extreme AX800XT /2DT, the EVGA E-GeForce 6800 Ultra, and the PNY Verto 6800GT PCI Express – offer two DVI ports, so you can set up dual LCDs using the digital ports, which typically provide a better image than do analog ports. All of the boards come with adaptors that convert the DVI port into a 15-pin analog connection.

S-Video-out, for hook up to a TV, is common to all the models, and about half offer composite-out, as well. Most of the boards with ATI graphics support S-Video-in, which is useful for capturing video into your PC, though in many cases you have to provide your own video-capture software. None of these cards come equipped with TV tuners.

Power, heat, and noise

As graphics boards get more powerful, they draw more power. However, all of the boards – even the EVGA E-GeForce 6800 Ultra, whose box specified that a 450-watt power supply was required – ran flawlessly on our test beds, which were outfitted with 300-watt power supplies.

NVidia says that it originally set the power specification for the 6800 Ultra chip to 480W in order to address the overclocking needs of gaming enthusiasts, who will get better performance out of a bigger power supply. NVidia has since lowered the official power spec to 350 watts.

Greater power generates more heat. Graphics processors soak up nearly as much power as your machine's processor, so these boards pack a heat sink and fan combination that can become hot, noisy, and bulky. Though only one AGP card, the Sapphire Toxic Radeon X800 Pro, was so large as to cover up our test bed's adjacent PCI slot, we left that next slot empty for all the boards, to help cool air flow to the fan and heat sink. Nevertheless, the cartoon-like blue fan with an orange shroud on the Sapphire board was one of the quietest. By contrast, ATI's and PowerColor's Radeon X800XT boards emitted louder, high-pitched fan noises.

The right upgrade

For best performance, get the latest drivers straight from the chip manufacturer – and update them regularly. The newest drivers may slightly raise your frame rate. And if you don't have at least a 2GHz CPU, you're better off investing in a new processor before you get a new graphics board. A slow processor can't properly feed top-of-the-line GeForce 6800- and Radeon X800-based boards.

Most boards require supplemental power from the same type of connector used for internal hard drives. It's a lot easier to insert the power connector before you put the board in the AGP or PCI Express slot.