Single Card (Crossfire)
"Wrapping things up, there’s little we need to say that wasn’t already evident in our graphs. The 6990 is a halo card and succeeds at such – by packing 2 Cayman GPUs on a single card, it is without question the fastest video card on the market today. At the same time there is and always will be a distinction between single-GPU cards and dual-GPU cards; the former is a threat to the latter, but the latter is rarely a threat to the former."
"Overall I consider the Radeon HD 6990 to be an excellent video card intended for affluent top-end gamers, but I suspect that the frame rate performance will sell more Antilles cards than multi-display Eyefinity support or added stereoscopic 3D functionality. If you can afford the asking price, the Radeon HD 6990 delivers the best graphics performance money can buy."
"The HD6990 is an impressive successor to the HD5970. AMD has once again shown that they still hold the crown of fastest overall video card."
"Just when we thought the graphics market was cooling down, AMD’s Radeon HD 6990 4GB has gone and set things alight once again. Its two Caymen XT GPUs simply deliver phenomenal performance, resoundingly beating the GeForce GTX 580 1.5GB in almost all of our tests. Only in Call of Duty: Black Ops at lower resolutions than 2,560 x 1,600 did the HD 6990 4GB fail to dominate the performance charts."
"With the release of the Radeon HD 6990, AMD brings an extraordinary performing product to the market. With dual-GPUs on one PCB, you always need to compromise a little here and there, but the overall package seems to work out really well. The x-factor is there and the performance is phenomenal when that 2nd GPU kicks in and if you like to go really wild with multiple-monitors then this product is starting to make a whole lot of sense."
"Going into this review, I was perfectly happy to set myself up for disappointment since dual GPU cards have almost always fell short of expectations. Whether it was driver issues, excess noise or something else, there has usually been some major pothole preventing me from buying what products like the GTX 295, HD 4870X2 and HD 5970 were trying to sell. AMD’s HD 6990 on the other hand has proven that my apprehension was misplaced as it threaded its way perfectly between the two other top-end Crossfire solutions. "
"The Radeon HD 6990 is being launched today, and we have full coverage of specifications and our gameplay experiences compared to several high-end dual-GPU solutions out there. If you are looking for a single video card package that packs a punch and provides headroom for hardware enthusiasts, this is a solid solution."
"The AMD Radeon 6990 is a graphics card which ensures enthusiasts need not make any compromises when gaming. It offers flawless performance from 1920×1080, right up to 5760×1080 and is priced very competitively."
"Ultimately, the Radeon HD 6990 4GB's main purpose isn't to offer value; it's to be the fastest graphics card around. It is that, and some, right now, but a green spectre looms distractingly large on the horizon. GeForce GTX 590 is the name and murdering the Radeon HD 6990 is very much the game. There can be only one sheriff of GPUville at any one time – no deputies here, thanks – and we can't wait until the twin gun-slinging GTX 590 rides in at the end of the month."
"While we wish power consumption was a bit lower and the card was a little quieter under load, we can’t help but be impressed by the AMD Radeon HD 6990. This graphics card is simply a beast, there’s no other way to put it. But AMD’s efforts to tame this beast must also be commended. Having tested single-GPU powered cards over the years that were much louder and didn’t offer anywhere near the kind of dominant performance that the Radeon HD 6990 does, we can better appreciate what AMD has done here. The Radeon HD 6990 is not everyone, as is evident by its exorbitant price tag and power requirements, but for those uncompromising enthusiasts that want nothing but the best of the best, at any price, the Radeon HD 6990 delivers the goods."
"AMD successfully pulled off the seemingly impossible: they married two Radeon HD 6970 GPUs on one PCB. A year ago nobody would have thought such an engineering feat possible. Modern high-end GPUs are limited by the power they can draw and the heat that amount of power generates. It is impressive to see so much rendering power combined in the fairly small volume of a dual slot graphics card. As a result the Radeon HD 6990 is the fastest graphics card in the world, it is leading NVIDIA's GeForce GTX 580 by a comfortable 30% performance margin."
"At present, in the suite of games we tested, AMD looks to have a performance advantage at several key price points. That may be a little jarring if your expectations were set several months ago, when we had something close to parity between red and green. We believe AMD has come by it honestly, delivering some impressive performance gains in recent driver releases. One of those changes, AMD tells us, is a revised resolve mechanism for multisampled antialiasing that improves frame rates generally when MSAA is in use—like in nearly all of our test scenarios—particularly in games that use deferred shading schemes. AMD's driver developers have made some notable progress in CrossFireX multi-GPU performance scaling, too. SLI scaling has long been one of the hallmarks of Nvidia's SLI, but AMD has closed that gap in recent months."
Two Cards (Quadfire)
"Don’t get me wrong, the HD 6990 is an awesome card to have, but HD 6990 CrossFireX will take some compelling to do. Is HD 6990 a nice graphics card? Yes. Should you look forward to NVIDIA’s upcoming dual-GPU graphics card? Yes, just in case. Should you look forward to NVIDIA’s upcoming dual-GPU card in SLI? Well, things are not encouraging, but the GPU vendors are not the ones to blame for."
"And as I write this, one day ahead of the launch, AMD refuses to comment on pricing. There’s also no official word on when enthusiasts will see the 6990 available to buy. We’re not worried, though. Skip the Radeon HD 6990 altogether and take advantage of fantastic CrossFire and SLI scaling using more elegant single-GPU cards. "