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Much-Improved Acoustics, With One Nagging Issue

AMD Radeon HD 7990: Eight Games And A Beastly Card For $1,000
By , Igor Wallossek

Cooling A More Elegant Solution

AMD buttons the Radeon HD 7990 up into a dual-slot card that only needs two eight-pin auxiliary power connectors to drive it. With that said, the card jams right up against the PCI-SIG’s electromechanical specification for one x16 slot and two eight-pin connectors: 375 W.

Even still, it’s impressive that AMD created a two-slot flagship after we’d seen nothing but bulkier solutions from PowerColor, HIS, and Asus. The company achieved this by screening out the best of the best ASICs prior to shipping off its Tahiti GPUs. For a while now, it’s been setting aside the top few percent of the lowest-power, highest-frequency parts, building up an inventory specifically for this launch. And while AMD’s partners are locked at certain voltage levels for their Tahiti-based products (inherently affecting power), AMD was able to drop the voltage on its special chips to still get up to 1 GHz out of them inside of a 375 W power limit. 

That’s not to say it’s easy to keep the Radeon HD 7990 cool (or even quiet, for that matter). Instead of the one axial fan Nvidia uses on its GeForce GTX 690, or even the centrifugal blower on Radeon HD 6990, AMD employs three axial fans on 7990. Their blades aren’t particularly thick, and the fans themselves aren’t reinforced for stability (you can rock them side-to-side with your fingers). But they spin slowly enough under typical gaming loads that they address the one thing that bothered me most about Radeon HD 6990: fan noise. In games, the 7990s fans are nearly imperceptible.

There is a price to be paid for this sort of design, though. Three fans, side-by-side, are only effective if they aren’t doing battle with each other. And that means channeling air vertically, rather than horizontally. At the end of the day, then, the slotted rear I/O panel that typically helps exhaust hot air from most graphics cards is almost non-functional. Instead, waste heat from both GPUs is jettisoned out the top of the card, right into your case. Consequently, you’ll want to be careful picking the right chassis for the Radeon HD 7990. AMD currently recommends two models: Antec’s Eleven Hundred with two 120 mm side-panel fans, and Cooler Master’s HAF-X, also with side-panel cooling. Enthusiasts who go a different route need to build with airflow in mind. Almost assuredly, small form-factor isn’t a viable option.

Physically, the Radeon HD 7990 measures the same 12-inches long as Radeon HD 6990. That’s an inch longer than GeForce GTX 690. Fortunately, both of its eight-pin power connectors are up on top of the board, so you don’t have to worry about leads extending another inch or two behind the already-long add-in. There’s also a metal plate on the back of the PCB. Given that the first fan’s blades protrude up above the plastic shroud a tad, you won’t want to put two 7990s right next to each other in a quad-CrossFire configuration.

Wait, What’s That Hum?

The Radeon HD 7990’s cooling fans spin quietly—something I was so happy AMD addressed. But another acoustic issue nagged at me. Previously, PowerColor sent in its AX7990 6GBD5-A2DHJ Devil13 for us to look at. But I was surprised at just how much noise the card’s inductors generated—like, I couldn’t believe an engineer would kick something like that out the door and expect someone to pay a grand for it.

To a lesser degree, the Radeon HD 7990 runs into something similar. AMD explained it to me as an artifact of oscillation between heavy and light workloads, where current draw spikes and dips, causing ceramic capacitors and the PCB itself to vibrate. The volume and tone of this phenomenon vary according to the task you’re performing, but it was noticeable enough during our real-world game testing with Bakersfield-based volunteers that several asked me to explain what was happening.

The solution is to turn on v-sync, capping the frame rate and preventing those highly variable loads. I don’t think it’s particularly ideal to have to use v-sync, but there it is. Igor in our German office created some video and performed frequency analysis that you’ll be looking at shortly. Decide for yourself if this is a deal-breaker.

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Top Comments
  • 26 Hide
    cangelini , April 23, 2013 9:53 PM
    donquad2001this test was 99% useless to the average gamer,Test the card at 1900x1080 like most of us use to get a real ideal of what its like,only your unigine benchmarks helped the average gamer,who cares what any card can do at a resolution we cant use anyway?

    If you're looking to game at 1920x1080, I can save you a ton of money by recommending something less than half as expensive. This card is for folks playing at 2560 *at least.* Next time, I'm looking to get FCAT running on a 7680x1440 array ;) 
  • 23 Hide
    timw03878 , April 23, 2013 9:47 PM
    Here's an idea. Take away the 8 games at 40 bucks a piece and deduct that from the insane 1000 price tag.
  • 12 Hide
    whyso , April 23, 2013 9:36 PM
    Power usage?

    Thats some nice gains from the prototype driver.
Other Comments
  • 12 Hide
    whyso , April 23, 2013 9:36 PM
    Power usage?

    Thats some nice gains from the prototype driver.
  • 12 Hide
    17seconds , April 23, 2013 9:37 PM
    Sort of seems like a mess to me. The game bundle is nice.
  • 23 Hide
    timw03878 , April 23, 2013 9:47 PM
    Here's an idea. Take away the 8 games at 40 bucks a piece and deduct that from the insane 1000 price tag.
  • 10 Hide
    cangelini , April 23, 2013 9:51 PM
    whysoPower usage?Thats some nice gains from the prototype driver.

    Power is the one thing I didn't have time for. We already know the 7990 is a 375 W card, while GTX 690 is a 300 W card, though. We also know AMD has Zero Core, which is going to shave off power at idle with one GPU shut off. I'm not expecting any surprises on power that those specs and technologies don't already insinuate.
  • -4 Hide
    ASHISH65 , April 23, 2013 9:51 PM
    nice article! here comes the Competitor of gtx 690!
  • 26 Hide
    cangelini , April 23, 2013 9:53 PM
    donquad2001this test was 99% useless to the average gamer,Test the card at 1900x1080 like most of us use to get a real ideal of what its like,only your unigine benchmarks helped the average gamer,who cares what any card can do at a resolution we cant use anyway?

    If you're looking to game at 1920x1080, I can save you a ton of money by recommending something less than half as expensive. This card is for folks playing at 2560 *at least.* Next time, I'm looking to get FCAT running on a 7680x1440 array ;) 
  • 2 Hide
    hero1 , April 23, 2013 9:54 PM
    Nice article. I was hopping that they would have addressed the whining but they haven't and that's a shame. Performance wise it can be matched by GTX 680 SLI and GTX 690 without the huge time variance and runt frames. Let's hope they fix their whining issue and FPS without forcing users to turn on V-sync. For now I know where my money is going consider that I have dealt with AMD before:XFX and Sapphire and didn't like the results (whining, artifacts, XF stops working etc). Sorry but I gave the red team a try and I will stick with Nvidia until AMD can prove that they have fixed their issues.
  • 1 Hide
    ohim , April 23, 2013 10:02 PM
    Why are all you people, that this card is not made for, complain about the price tag? AMD / Nvidia for sure don`t really make a profit if any out of these monsters. They are just for show like in the CPU business.
    People mostly buy Intel (I3/i5 a lot more than i7) just because Intel can provide top of the line CPUs in the i7 Extreme range. Same goes here, if some hears that AMD has a better 1000$ card than Nvidia, they will probably spend 100-200$ for an AMD card and not Nvidia.
    Power ... unless you`re not a guy who saves 2 years in a row for this card to have a 6 months nerd gaming glory you won`t care that much how power hungry this card is.

    Is just like asking Ferrari or Lamborghini how many mpg their cars do.
  • 6 Hide
    mayankleoboy1 , April 23, 2013 10:14 PM
    1.I wonder if inserting all those pauses in the rendering pipeline for smoothness harms the compute performance.

    2. Regarding the fan noise and the hum : It would be interesting to know how much noticable is the fan noise and the hum with increaseing listner distance. IOW, which noise is more noticable at near/medium/far distances ?


    Drivers still are AMD's biggest weakness. I would have expected AMD to havetop-notch , A-one drivers to go with the HD7990. After all, this is AMD's halo product. The first impression is what matters. The conclusion is basically "Card is good. Drivers are poor, with better coming in future". So ultimately its selling a promise, which may/may not succeed. It appears to me that AMD doesnt value its own products.
  • -1 Hide
    mayankleoboy1 , April 23, 2013 10:18 PM
    Ohh, and a video conversion test would have been nice too. (Is there any software available that supports CFX ?)
    Also, has the Video Conversion Engine in AMD taken off ?
  • 0 Hide
    jezus53 , April 23, 2013 10:26 PM
    It's very interesting that AMD couldn't find a capacitor that wouldn't cause this noise. I feel once third party vendors get the reference they'll find ways of removing that. Hope they fix it soon or else nVidia will have a new line of cards while AMD is having problems with neatly two year old chips!!!
  • 1 Hide
    dragonsqrrl , April 23, 2013 10:41 PM
    hero1Nice article. I was hopping that they would have addressed the whining but they haven't and that's a shame. Performance wise it can be matched by GTX 680 SLI and GTX 690 without the huge time variance and runt frames. Let's hope they fix their whining issue and FPS without forcing users to turn on V-sync. For now I know where my money is going consider that I have dealt with AMD before:XFX and Sapphire and didn't like the results (whining, artifacts, XF stops working etc). Sorry but I gave the red team a try and I will stick with Nvidia until AMD can prove that they have fixed their issues.

    Unfortunately I'm really not sure the whining issue is something that can be fixed with a driver update. I think it has more to do with the hardware on the board than anything else. But it's good to see that AMD has finally recognized the frame time variance and micro-stutter problem, and are actively pursuing a solution. Although the test in the review was limited, I think it's telling that every gamer tested was able to recognize the difference between AMD and Nvidia cards, and even the difference brought by AMD's own prototype drivers.
  • 2 Hide
    hero1 , April 23, 2013 10:51 PM
    dragonsqrrlUnfortunately I'm really not sure the whining issue is something that can be fixed with a driver update. I think it has more to do with the hardware on the board than anything else. But it's good to see that AMD has finally recognized the frame time variance and micro-stutter problem, and are actively pursing a solution. Although the test in the review was limited, I think it's telling that every gamer tested was able to recognize the difference between AMD and Nvidia cards, and even the difference brought by AMD's own prototype drivers.


    I know and that's what I meant by hopping that they would have addressed the whining with this card. It happens to all their cards, well the ones that I have owned especially the XFX and if they knew what causes then they should have fixed it.

    Let's hope that the prototype driver will also translate to better drivers for all their GPUs and address the frame rate issues. Other than that, it is a good card but I think, for my personal use since I was waiting to see what this can offer, I will just get the GTX 680 or the GTX 780 next month and will definitely go back to AMD if they address those issues.
  • 2 Hide
    dragonsqrrl , April 23, 2013 10:54 PM
    whysoPower usage?Thats some nice gains from the prototype driver.


    For everyone seeking power and heat results:
    http://www.anandtech.com/show/6915/amd-radeon-hd-7990-review-7990-gets-official/16

    It consumes a lot of power under load, substantially more than the GTX690, but like Chris said that's to be expected. The big difference with the 7990 seems to be acoustics in relation to temps at load. It's a massive improvement over the 6990, and pretty much on par with the GTX690. Unfortunately the coil whine seems to undo a lot of the improvements made to the stock cooler, but all things considered it's pretty impressive what AMD was able to do in this area, especially in comparison to unofficial solutions from other vendors (dual slot, only requires 2 8-pin).
  • 2 Hide
    dragonsqrrl , April 23, 2013 10:57 PM
    hero1I know and that's what I meant by hopping that they would have addressed the whining with this card.

    Sorry, that's a reading fail on my part. Thought you said, 'hope they'll address the whining' or something to that effect.
  • 2 Hide
    hero1 , April 23, 2013 11:00 PM
    dragonsqrrlSorry, that's a reading fail on my part. Thought you said, 'hope they'll address the whining' or something to that effect.


    No problem.
  • 5 Hide
    bartholomew , April 23, 2013 11:32 PM
    A Price tag of $849.99 would had been quite aggressive & increased its value significantly.
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