AMD's Malta Becomes The Radeon HD 7990
Time flies. We published AMD Radeon HD 7970: Promising Performance, Paper-Launched almost a year and a half ago. The graphics card market was quite a bit different back then. AMD’s virginal Graphics Core Next architecture made its debut against Nvidia’s Fermi-based GeForce GTX 580, absolutely blowing the company’s own Radeon HD 6970 out of the water in the process.
And a dual-GPU card, based on two of the 7970’s Tahiti GPUs was rumored to be right around the corner. We waited. And we waited.
Of course, in the 12 months that followed, no official Radeon HD 7990 surfaced. Rather, board partners tentatively dipped their toes into that high-end space. PowerColor got out ahead of the rest with a dual-Tahiti offering that consumed three expansion slots, required three eight-pin auxiliary power connectors, and screamed like a banshee any time we applied a load to it. HIS followed suit, giving us exclusive access to a couple of prototypes before withdrawing its plans to ship a dual-GPU solution altogether. Finally, Asus threw its hat into the ring with a liquid-cooled card of its own, as obscenely-priced and limited as it was. We looked at all of them in Asus' ROG Ares II: Four Dual-GPU Graphics Cards, Compared, eventually coming to the conclusion that Nvidia’s GeForce GTX 690, while a bit slower in our benchmarks, made more sense than any of the Radeons.
Challenge accepted, AMD said. Today we have a real, actual Radeon HD 7990, straight from the company’s own product team. It’s a dual-slot card. It only requires two eight-pin power connectors. And—brace yourself—its fans spin quietly. That’s not to say the 7990 is silent, but more on that later.
Hold Nothing Back In The Name Of Performance
Stripped down to its bare PCB, the Radeon HD 7990 consists of two Tahiti GPUs, each surrounded by 3 GB of GDDR5 memory and connected by a PLX Technology PEX 8747 switch.
The graphics processors are complete—AMD doesn’t disable any of their resources, so each brings 2,048 Stream processors to the table, along with 128 texture units, 32 ROPs, and an aggregate 384-bit memory bus. The company even sets the GPUs to operate at 950 MHz, with a 1 GHz boost state. That’s a little faster than the vanilla Radeon HD 7970, and a bit slower than the later GHz Edition version, which starts at 1 GHz and accelerates to 1.05 GHz.
The 3 GB of GDDR5 memory attached to each GPU runs at 1.5 GHz, just like AMD’s Radeon HD 7970 GHz Edition (in comparison, the original 7970 launched with a 1,375 MHz memory clock), delivering up to 288 GB/s per GPU.
Nestled between the two 4.3 billion-transistor chips is that PEX 8747 switch—the same one Nvidia uses to enable inter-GPU communication on the GeForce GTX 690. The 48-lane, five-port device is manufactured at 40 nm and is PCI Express 3.0-capable. So, it attaches to each GPU through a 16-lane link, and then to the host interface with an additional 16 lanes.
All of that hardware is used to enable up to five simultaneous display outputs, one of which comes from dual-link DVI and four of which get exposed through mini-DisplayPort connectors. In comparison, Nvidia’s GeForce GTX 690 can only do four monitors in a three-plus-one configuration. Five screens in a 5 x 1 arrangement make far more sense to productivity-oriented enthusiasts.
At least based on its raw specifications, the Radeon HD 7990 is technically closer to two 7970 GHz Editions in CrossFire than GeForce GTX 690 is to two 680s in SLI. And given the massive performance boosts we’ve seen from AMD’s driver team over the last year, the paper promise is a compelling advantage that should make this the fastest dual-slot graphics card in existence. Now, what about the rest of the board’s vitals?
|Header Cell - Column 0||Radeon HD 7990||Radeon HD 7970 GHz Ed.||GeForce GTX Titan||GeForce GTX 690||GeForce GTX 680|
|Shaders||2 x 2,048||2,048||2,688||2 x 1,536||1,536|
|Texture Units||2 x 128||128||224||2 x 128||128|
|Full Color ROPs||2 x 32||32||48||2 x 32||32|
|Graphics Clock||950 MHz||1,000 MHz||836 MHz||915 MHz||1,006 MHz|
|Texture Fillrate||2 x 121.6 GT/s||128 Gtex/s||187.5 Gtex/s||2 x 117.1 Gtex/s||128.8 Gtex/s|
|Memory Clock||1,500 MHz||1,500 MHz||1,502 MHz||1,502 MHz||1,502 MHz|
|Memory Bus||2 x 384-bit||384-bit||384-bit||2 x 256-bit||256-bit|
|Memory Bandwidth||2 x 288 GB/s||288 GB/s||288.4 GB/s||2 x 192.3 GB/s||192.3 GB/s|
|Graphics RAM||2 x 3 GB GDDR5||3 GB GDDR5||6 GB GDDR5||2 x 2 GB GDDR5||2 GB GDDR5|
|Die Size||2 x 365 mm2||365 mm2||551 mm2||2 x 294 mm2||294 mm2|
|Transistors (Billion)||2 x 4.31||4.31||7.1||2 x 3.54||3.54|
|Process Technology||28 nm||28 nm||28 nm||28 nm||28 nm|
|Power Connectors||2 x 8-pin||1 x 8-pin, 1 x 6-pin||1 x 8-pin, 1 x 6-pin||2 x 8-pin||2 x 6-pin|
|Maximum Power||375 W||250 W||250 W||300 W||195 W|
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If I had 1,000 dollars... I would buy a Titan. Its power efficiency, drivers and uber-chip goodness is unmatched.Reply
Thats some nice gains from the prototype driver.
Nice article!! Unbeatable performance out of the box.Reply
Sort of seems like a mess to me. The game bundle is nice.Reply
Here's an idea. Take away the 8 games at 40 bucks a piece and deduct that from the insane 1000 price tag.Reply
this 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?Reply
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.Reply
nice article! here comes the Competitor of gtx 690!Reply
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 ;)Reply
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.Reply