Final Thoughts

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 two 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.

When we reviewed the Radeon HD 5970 back in 2009, the principle question we ran in to was whether it would be better to have a 5970 or two 5850s in CrossFire, given that the two were nearly identical in performance. The answer was that CrossFire was superior so long as you had a power supply with four readily available PCIe power plugs. With the Radeon HD 6990, we find ourselves asking the same question and an even more direct answer. With but a trio of exceptions, the 6990 doesn’t make sense compared to a pair of cards in CrossFire.

The reasons for this are numerous. The 6990 is so close to the 6950CF in performance that on average at 2560 the two are identical. It’s only in Bad Company 2 and Stalker that we see the 6990 take an advantage, which is then negated by anything from Civilization V to DIRT 2. Meanwhile the 6950CF is cooler, significantly quieter, and less power hungry than the 6990. And finally the 6950CF is cheaper: we can snag a pair of cards for $520, versus $700 for the 6990. Likewise, for $640 you can have a pair of 6970s and enjoy performance at 2560 roughly 8% ahead of the 6990, and that setup is still quieter than the 6990.

This leads us to our exceptions, and why we believe the 6990 is truly a niche product.

  1. Quad-CrossFire; this is going to be the highest performing AMD solution at this time, power and noise be damned. This requires a motherboard with PEG slots three slots apart (lest you choke the first 6990), but it’s achievable.
  2. 5x1P Eyefinity. At five-panel resolutions you’re going need a pair of powerful GPUs, but given AMD’s CrossFire Eyefinity limitations at the time only 2 cards can directly drive five monitors: the 5870 Eyefinity 6, and the 6990. Ultimately MST hubs will allow the 6970CF to do this, but for the time being the 6970CF is limited by the number of displays a single card can drive without a hub.
  3. If you absolutely cannot fit two cards in your computer. This is often the traditional domain of the dual-GPU card, but the 6990’s cooling and power requirements put this in jeopardy. Most micro-ATX cases would simply not be suitable due to cooling needs, meanwhile motherboards with two or more PEG slots are increasingly common. There are very few computers with a single PEG slot that could power and cool the 6990 without a complete overhaul in the first place.

Dual-GPU cards have always been a niche product, but the 6990 really takes this and runs with it. There’s no significant power/noise savings to be found by consolidating two GPUs on to a single card, and as we said earlier with the dual-exhaust cooler the 6990 is effectively two video cards on one PCB. This isn’t a bad thing – the 6990 is the world’s fastest video card after all – but it drives the card in to some very specific niches. If you fall in to these niches, then the 6990 is certainly the card for you. At 22% faster than the 5970 it isn’t a massive performance boost, but it certainly has earned its place.

But if you don't fall into these niches, then there’s nothing the Radeon HD 6990 offers you today that the 6950/6970 didn’t offer in CrossFire mode yesterday. In this case while AMD’s king card is an engineering marvel for its ability to handle so much power in a confined space, as a product on the market it won’t be quite as significant as the title implies.

Power, Temperature, and Noise: How Loud Can One Card Get?
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  • james.jwb - Tuesday, March 08, 2011 - link

    I doubt it. That would be 80 dBA at ear level compared to whatever Ryan used. At ear level it's going to be a lot lower than 80.

    Still, that doesn't take away the fact that this card is insane...
    Reply
  • Belard - Tuesday, March 08, 2011 - link

    The card needs 3 slots to keep cool and such. They should have made a 2.5-slotted card, but with a bit of a twist.

    Channel the AIR from the front GPU chamber into a U-duct, then split into a Y that goes around the fan (which can still be made bigger. The ducts then exhaust out the back in a "3rd slot". Or a duct runs along the top of the card (out of spec a bit) to allow the fan more air space. It would add about $5 for more plastic.

    Rather than blowing HOT air INTO the case (which would then recycle BACK into the card!
    OR - blowing HOT air out the front and onto your foot or arm.

    Noise is a deal killer for many people nowadays.
    Reply
  • strikeback03 - Tuesday, March 08, 2011 - link

    That ductwork would substantially reduce the airflow, making a sharp turn like that would be a large bottleneck. Reply
  • burner1980 - Tuesday, March 08, 2011 - link

    I´m always wondering why reviews always neglect this topic. Can this card run 3 monitors @ 1920x1080p 120 HZ. 120 HZ monitors/beamer offer not only 3D but foremost smooth transitions and less screen tearing. Since this technique is available and getting more and more friends, I really would like to see it tested.
    Can anybody enlighten me ? (I know that Dual link is necessary for every display and that AMD had problems with 120 HZ+eyefinity) Did they improve?
    Reply
  • silverblue - Tuesday, March 08, 2011 - link

    ...with two slightly downclocked 6950s. Alternatively, a 6890, albeit with the old VLIW5 shader setup. As we've seen, the 5970 can win a test or two thanks to this even with a substantial clock speed disparity.

    The 6990 is stunning but I couldn't ever imagine the effort required to set up a machine capable of adequately running one... and don't get me started on two.
    Reply
  • Figaro56 - Tuesday, March 08, 2011 - link

    I'd love to see Jessica Alba's beaver, but that aint going to happen either. Reply
  • qwertymac93 - Tuesday, March 08, 2011 - link

    AUSUM SWITCH

    http://img202.imageshack.us/img202/8717/ausum.png
    Reply
  • KaelynTheDove - Tuesday, March 08, 2011 - link

    Could someone please confirm if this card supports 30-bit colour?

    Previously, only AMD's professional cards supported 30-bit colour, with the exception of the 5970. I will buy either the 6990 or Nvidia's Quadro based on this single feature.

    (Because somebody will inevitably say that I don't need or want 30-bit colour, I have a completely hardware-calibrated workflow with a 30" display with 110% AdobeRGB, 30-bit IPS panel and the required DisplayPort cables. Using 24-bit colour with my 5870 CF I suffer from _very_ nasty posterisation when working with high-gamut photographs. Yes, my cameras have a colour space far above sRGB. Yes, my printers have it too.)
    Reply
  • Gainward - Tuesday, March 08, 2011 - link

    Just a heads up for anyone buying the card and wanting to remove the stock cooler.... There is a small screw on the back that is covered by two stickers with (its under the two stickers that look like a barcode). Well removing that you will then notice a void logo underneath it... I just wanted to point it out to you all...

    Didnt bother us too much here seen as ours is sample but I know to some droppin £550ish UK is quite a bit of cash and if all you are doing is having an inquisitive look it seems a shame to void your warranty :-S
    Reply
  • mmsmsy - Tuesday, March 08, 2011 - link

    I'd like to know how do you benchmark those cards in Civ V. I suppose it's the in-game benchmark, isn't it? Well, I read some tests on one site using their own test recorded after some time spent in the game using FRAPS and I'm wondering if using the in-game test is that really different scenario. According to the source, in the real world situation nVidia cards' performance show no improvement whatsoever over AMD's offerings. If you could investigate that matter it would be great. Reply

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