AMD Radeon HD 6990 review

It’s possible to extract a little more performance from this monstrous card, too, via a tiny switch near the PCI bracket. Flip it, and you’ll change from the standard BIOS to an overclocked version that restores each core’s base clock to 880MHz, upping the maximum theoretical power consumption from 375W to a huge 450W.

While that’s a sizeable boost on paper, it disappointed in the real world. It added just 1fps to the average in that most demanding Crysis test, a measly 2fps to the toughest Just Cause 2 benchmark, and 3fps to our toughest Stalker result. In fact, the only area that saw a meaningful rise was the one we didn’t want: with the standard BIOS our whole test rig drew a peak of 423W, but the overclocked settings upped that to 477W. It requires two eight-pin power cables too.

That begins the caveats, of which there are several. The most obvious is the HD 6990’s sheer size, with its 305mm length proving too much even for our large Cooler Master CM 690 II Advanced test chassis. To fit the card inside, we had to remove its hard disk cage and use the motherboard’s lowest PCI Express x16 slot – and you’ll have to screw it in carefully to make sure the 1.14kg weight is amply supported.

The HD 6990 isn’t overly noisy when idle, but it’s one seriously loud card when the games get going. The single fan ramped up to levels of noise we thought we’d left behind when the GTX 480 was retired. With the boost switch enabled it was louder still.

At least the pair of vapour-chamber coolers kept the GPUs relatively chilled, with the cores peaking at 83°C in normal mode and 84°C when boosted. It’s a little higher than we’d like, but it doesn’t hit truly dangerous heat levels.

And then there’s the biggest issue of all: the astronomical price. Although you could argue it’s launching at a similar price to its predecessor, an expected £560 inc VAT is still a faintly ludicrous amount of money to be spending on a single component in your PC. This record-breaking power will be the preserve of those for whom money really isn’t a consideration, and those lucky people can enjoy the HD 6990’s blistering power on their 30in TFTs with all the settings to maximum. Maybe they’ll let the rest of us come round and watch.