AMD Radeon HD 7990 Review: The Quiet Beast - HotHardware

AMD Radeon HD 7990 Review: The Quiet Beast

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A quick glance at the Radeon HD 7990 reveals that this is no run-of-the-mill graphics card. Not only is the Radeon HD 7990 a beast at a full 12” in length, but it sports a newly-designed shroud, three huge cooling fans, and massive heatsink assembly with a dense array of aluminum fins.

Although it looks like there’s only one, gigantic heatsink underneath that fan shroud, there are actually two—one for each GPU. The dual heatsinks each have a copper base, linked to the aluminum thin fins via four copper heatpipes. The three axial fans on the card blow air down onto the heatsinks, where some air is expelled from the case through a vent in the font, but a majority is circulated back into the case. In fact, air is actually expelled from the card in every direction. We should mention that in addition to high-performance, the cooler on the Radeon HD 7990 is designed to be quiet as well—much quieter than previous Radeon HD 7900 series products. But we’ll touch more on that subject later.

The Radeon HD 7990 needs such a large cooling assembly because it is essentially a pair of Radeon HD 7970 GHz Editions crammed onto a single PCB, with just slightly lower GPU clocks. The two Tahiti GPUs powering the card have a peak boost clock of 1GHz (the Radeon HD 7970 GHz Edition boosts to 1050MHz) and they’re each paired to 3GBs of GDDR5 memory clocked at 1.5GHz (6 Gbps, effective), via a 256-bit memory bus, for a total of 6GB of on-board memory. The aggregate effect of having the two GPUs results in a grand total of 4096 stream processors, 256 texture units, 64 ROPs, and a combined 8.6B transistors. Compute performance peaks at 8.2 TFLOPS, with a 256 GT/s textured fillrate and a massive 576 GB/s of memory bandwidth.

The two GPUs on the card are linked together via a 48-lane PCI Express Gen 3 PLX bridge chip that offers 96GB/s of inter-GPU bandwidth.

In addition to the newly-designed cooling hardware, the Radeon HD 7990 is outfitted with a heatplate on the backside of the PCB, which also adds rigidity and the card sports an all-digital PWM. Like AMD's previous dual-GPU flagship, the Radeon HD 6990, the Radeon HD 7990 requires a pair of supplemental 8-pin PCI Express power feeds. Take all of the goodies on a Radeon HD 7970, double ‘em up, cram them only a single PCB and you’ve got a Radeon HD 7990.

The output configuration on the Radeon HD 7990 consists of four mini-DisplayPorts and a single dual-link DVI output. And, of course, the card supports AMD’s multi-display Eyefinity technology, with up to five independent displays running simultaneously. Technically, with two Tahiti GPUs, the card has the ability to output video to 12 displays (6 per GPU), but only five outputs are on the card. Perhaps on of AMD’s board partners will get a little nutty and expose more.
 

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Actually I wouldn't be surprised if the fix for the stuttering actually increases performance. It is an area that AMD was not looking at before and they have been finding performance that was "left on the table".

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Just read through a few reviews. Looks like CF issues are stopping this card just short at times. I thought it would go for 800-900, not 1000. At that price, the 690 performs more consistently, but if you play at above 1200p the 7990 is a better choice because it pulls ahead there by 5-10% at times (i.e. when there arent cf issues). Hoping new drivers will fix that.

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Well everything I read AMD says the issue is just software that is needing to be optimized which I would think might give it more performance like InfinityzeN1 said. I really think AMD is getting on its game with GPUs lately and when they catch up with the software side they just might be really giving Nvidia a run for their money. 

The price wasn't a shock considering the earlier reports that the 7990 can beat both the 690 and Titan. Time will well what happens in the next couple months with what AMD does with the drivers.

Also top notch review Yes Now I just need to know where I can get a couple of these to "fall off" a truck somewhere :P

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Nice review Marco! Sure are some beastly cards out there nowadays. Thanks for the hard work getting the latency info included!

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Working on an update now using the prototype drivers that address some of the frame pacing issues...

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Very nice article... but I'm just not impressed with the card. Seems like the only time AMD/ATI video cards become the best performing is when they just double up the number of GPUs on the card. Additionally, the drivers for these cards have a very long history of falling just short of the mark.

Nvidia could cheese out and just slap two GPUs in one of their cards like AMD just did... instead they innovate and develop faster/better/more advanced GPUs.

Maybe I've just been soured about AMD over the years, but this doesn't strike me as innovative and I'd rather have an Nvidia based Titan or 690 or even a pair of 680's over this card.

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In what way is a 690 not just slapping 2 GPUs on one card?

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Yeah man that is all the 690 is. Just two 680s combined. If AMD fixes the driver issue which hopefully they will then Nvidia might be taking a backseat until the 700 series are released. In the end it will always go back and forth though. 

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Ahh my mistake. I guess Nvidia did cheese out then. I wasn't aware that the 690 was just 2 GPU's on the same card.

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Heh well I know both Nvidia and AMD have done dual GPU cards for the last few series. It's not like one does it only then they decide to copy them. Nvidia brought out the 690 a year ago and AMD just now because of the demand since ASUS had the only real viable dual 7000 series GPU in the Ares II.

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