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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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  • MarkLuvsCS - Tuesday, March 08, 2011 - link

    Thanks for an awesome article!

    Minor typo in section "ONCE AGAIN THE CARD THEY BEG YOU TO OVERCLOCK" second to last paragraph second sentence says "...the 6690OC’s core clock is only 6% faster and the memory clock is the same, versus..."
    Reply
  • Figaro56 - Tuesday, March 08, 2011 - link

    Yes this is the article I as waiting for. Time to get rid of my 2 HD 5870 cards and purchase 2 HD 6970 ones. I wouldn't get an HD 6990. That is pretty clear.

    Thanks AnAndTech!
    Reply
  • mino - Tuesday, March 08, 2011 - link

    AT has CHOSEN to not overclock the card based on its THEORETHICAL (Furmark) load temperatures ...

    Go bash AT for writing "OC" on the slides while they enabled ONLY the performance BIOS. Not doing ANY overclocking whatsoever by fear of Furmark ...

    In effect what they have done was in effect a factory OC, not a traditional OC of the what-it-can-handle kind.

    Great, so Furmark has achieved one more evil goal: it prevents (AT?) journalists to do overclocking reviews ...
    Reply
  • mino - Tuesday, March 08, 2011 - link

    Here come some real OC numbers: www.legitreviews.com/article/1566/14

    BTW, they did not even bother with the #1 BIOS option to achieve it ... so, lets talk about biased reviewing, shall we?
    Reply
  • RaistlinZ - Tuesday, March 08, 2011 - link

    Looks like the 2x6950 is a much better option, given you'll have much less noise to deal with and that they can be flashed to 6970 shaders.

    If this card had been $599 I probably would have picked one up. But at $699 I think I'll just wait for 28nm generation of cards.

    Thanks for trying, AMD.
    Reply
  • MarcHFR - Tuesday, March 08, 2011 - link

    Hi,

    Drivers used are :

    NVIDIA ForceWare 262.99
    NVIDIA ForceWare 266.56 Beta
    NVIDIA ForceWare 266.58
    AMD Catalyst 10.10e
    AMD Catalyst 11.1a Hotfix
    AMD Catalyst 11.4 Preview

    Is it possible to know wich driver is used for each card ?

    Thanks
    Reply
  • jcandle - Tuesday, March 08, 2011 - link

    Ryan, any chance you'll be doing a thermal compound review soon? 8% against their stock compound. How much better is it than current performance aftermarket compounds? Reply
  • IanCutress - Tuesday, March 08, 2011 - link

    Quite difficult to get accurate thermal compound numbers. There's no way you can guarantee that the compound will be spread evenly and accurately every time. Any big 8ºC differences will show sure, but you're always playing with statistics to +/- 3ºC. Then there's the inevitable argument about the right way to apply the paste... Reply
  • 7Enigma - Tuesday, March 08, 2011 - link

    More importantly is the normal compound most manufacturers use is junk compared to a good thermal compound such as arctic silver (don't keep up on the latest brands as I still have Arctic Silver 3 that works great for me). So that 8% might very well be true since the normal stuff is of poor quality. Reply
  • ypsylon - Tuesday, March 08, 2011 - link

    But few issues need to be addressed. Noise for starters, nearly 80dBA. Thats like working in a foundry. Also cooling is highly inefficient for card of this size. Need some 3rd party solution or water cooling altogether.

    Biggest problem for 6990 could be (or rather will be) nVidia. If they price GTX590 at the same level or even below $700 price tag then AMD will be screwed totally. For now waiting for GTX590 and 6990 with some after market coolers as stock solutions are completely unacceptable.

    One thing straight - I do not sleep on ca$h and if I buy 6990/590 it will be ma$$ive expense for me, but... What swings things for me with cards like this, is that I do not need uber VGA for 30 monitors. All I want is card with large frame buffer, which will live in my PC for ~10 years without need to upgrade, and it will occupy only 1 PCI-ex x16 slot. SLI/CF is totally misguided if you do have some more hardware installed inside. Sometimes (with all that SLI/CF popularity) I wonder, why 7 slot ATX is still alive and 10-12 slot motherboards are not a standard?
    Reply

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