A sample of AMD's next-generation Radeon HD 7970 landed in our lab just before Santa. Don't cross your fingers for one of these in your stocking, though. It's not available yet. Is it fast, though? Our benchmarks suggest yes, but more testing remains!
Leading into December, we didn’t really expect to see a next-generation of graphic card in the 31 days before 2012. In fact, even mid-month, after we’d already been briefed, the plan was to launch in January. Windows 8 and its accompanying DirectX 11.1 API update aren’t expected for months still, and today’s high-end graphics cards are well-equipped to handle modern games. Despite the fact that AMD purportedly stopped production of its Radeon HD 6990 months ago, we were worried that rumors of poor 28 nm yields at TSMC meant there was no way a new GPU could be readied in time.
When AMD moved its launch date up to today, we were even more bowled over. The official line from AMD was that “After collecting feedback from our partners and evaluating our overall readiness…we believe this new date allows us to get ahead of the Christmas season rush and CES.” Getting ahead of the Christmas rush by launching 72 hours before the big day is a tough line to swallow, especially after a follow-up confirming that cards won't be shipping until January 9th. The unfortunate result is that a lot of AMD’s software partners were unprepared to provide us with the applications needed to properly test the GPU’s new features. So, this article officially goes down as a preview, rather than a review. We will, of course, follow up when all of the proper tools are available for testing.
Meet Radeon HD 7970
Regardless of whether or not it’s ready for the world, or the world is ready for it, AMD’s Radeon HD 7970 is up and running in the Tom’s Hardware lab. This card is no minor revision of the Radeon HD 6000 series. The company’s ”Southern Islands” architecture was re-designed from the ground up with a long list of new features and capabilities, including DirectX 11.1 compatibility. Composed of 4.31 billion transistors etched on a 28 nm process, the flagship Tahiti GPU sports about 160% of the Cayman design’s reported transistor count. However, adopting the latest lithography node allows AMD to cram that extra complexity into a 365 mm² die, which is smaller than its predecessor’s 389 mm² surface area.
Before we delve into the major architectural redesign, let’s have a closer look at the new card’s specifications compared to its competition.
| Radeon HD 7970 | Radeon HD 6970 | Radeon HD 6990 | GeForce GTX 580 | |
|---|---|---|---|---|
| Stream processors | 2048 | 1536 | 3072 | 512 |
| Texture Units | 128 | 96 | 192 | 64 |
| Full Color ROPs | 32 | 32 | 64 | 48 |
| Graphics (Shdr) Clock | 925 MHz | 880 MHz | 830 MHz | 772 (1544) MHz |
| Texture Fillrate | 118.4 Gtex/s | 84.5 Gtex/s | 159.4 Gtex/s | 49.4 Gtex/s |
| Memory Clock | 1375 MHz | 1375 MHz | 1250 MHz | 1002 MHz |
| Memory Bus | 384-bit | 256-bit | 2x 256-bit | 384-bit |
| Memory Bandwidth | 264 GB/s | 160 GB/s | 160 GB/s | 192.4 GB/s |
| Graphics RAM | 3 GB GDDR5 | 2 GB GDDR5 | 2 GB GDDR5 | 1.5-3 GB GDDR5 |
| Die Size | 365 mm2 | 389 mm2 | 2 x 389 mm2 | 520 mm2 |
| Transistors (Billion) | 4.31 | 2.64 | 5.28 | 3 |
| Process Technology | 28 nm | 40 nm | 40 nm | 40 nm |
| Power Connectors | 1 x 8-pin, 1 x 6-pin | 1 x 8-pin, 1 x 6-pin | 2 x 8-pin | 1 x 8-pin, 1 x 6-pin |
| Maximum power (TDP) | 250 W | 250 W | 375 W | 244 W |
| Price | $549 MSRP | $340-$380 (Newegg) | $700-$750 (EOL) | $500-$530 (1.5 GB) $590-$730 (3 GB) |
This product boasts notable advantages over the Radeon HD 6970, with 33% more stream processors and texture units, and a 65% net memory bandwidth increase thanks to its 384-bit memory bus. The only specifications that these cards share are 32 ROPs and a 250 W TDP. Based on those figures alone (and the fact that this is apparently going to be a $550 card), we’d expect the Radeon HD 7970 to decimate the 6970, edge past the GeForce GTX 580, and fall behind AMD’s Radeon HD 6990. There’s frankly a lot more to this story than gaming performance, though, and we’ll get to that in an in-depth exploration of AMD’s new Graphics Core Next architecture.
But first, we’ll share what we know about the Radeon HD 7000 series. Despite rumors to the contrary, all of the 28 nm Radeon 7000 series GPUs, previously code-named Southern Islands, are based on the Graphics Core Next architecture. That includes the Radeon HD 7700 series (Cape Verde Core), 7800 series (Pitcairn), and 7900 series (Tahiti), at the very least. AMD may include some 40 nm products under the 7000-series umbrella, and those would employ rebranded VLIW4/5 architectures.
The Southern Islands-based cards share the same features and abilities, which is good news. Here is a slide showing the placement of new product families relative to the Radeon HD 6000 series:
As you’ll see in our tests, the Radeon HD 7900 series appears to perform as its position in the deck would suggest. Note the Q1, 2012 expected date and the unnamed dual-GPU product at the top of the food chain.
With the relative performance of Radeon HD 7000-series cards established by AMD’s marketing department, let’s have a look at the family’s unique features. We’ll start with the basics: the Southern Islands architecture.
Our original plan was to test Radeon HD 7970 on an X79-based platform with Core i7-3960X. However, AMD pulled the rug out from under us as our desired platform was en route to the snowy whiteness that is Canada in December. Instead, we were forced to run all of our performance data on an admittedly more common LGA 1155-based Core i5-2500K overclocked to 4 GHz. The Sandy Bridge-E-based testing will have to wait until next month, when AMD lets its next batch of information spill on the 7900-series family.
| Test Hardware | |
|---|---|
| Processor | Intel Core i5-2500K (Sandy Bridge) Overclocked to 4 GHz, 6 MB L3 Cache, power-saving settings enabled, Turbo Boost disabled. |
| Motherboard | MSI P67A-GD65, Intel P67 Chipset |
| Memory | OCZ DDR3-2000, 2 x 2 GB, at 1338 MT/s, CL 9-9-9-20-1T |
| Hard Drive | Western Digital Caviar Black 750 GB, 7200 RPM, 32 MB Cache, SATA 3Gb/s Samsung 470 Series SSD 256 GB, SATA 3Gb/s |
| Graphics Cards | Radeon HD 7970 3 GB GDDR5 Radeon HD 6970 2 GB GDDR5 Radeon HD 6990 4 GB GDDR5 GeForce GTX 580 1.5 GB GDDR5 GeForce GTX 590 3 GB GDDR5 |
| Power Supply | Seasonic X760 SS-760KM: ATX12V v2.3, EPS12V, 80 PLUS Gold |
| CPU Cooler | Cooler Master Hyper TX 2 |
| System Software And Drivers | |
| Operating System | Microsoft Windows 7 Ultimate x64 |
| DirectX Version | DirectX 11 |
| Graphics Driver | GeForce: 285.88 Beta |
| Radeon: 7900 Launch Beta Driver | |
| Synthetic Benchmarks | |
| 3DMark 11 | Version 1.0.3.0, Extreme Preset |
| Unigine Heaven | Version 2.1, two runs, Tessellation Off and Tessellation Normal |
| Games | |
| Battlefield 3 | Version 1.0.0.0, Operation Swordbreaker, Fraps Run |
| Batman: Arkham City | Version 1.0.0.0, Built-In Benchmark |
| Metro 2033 | Version 1.0.0.1, Built-In Benchmark |
| DiRT 3 | Version 1.2.0.0, Built-In Benchmark |
| Crysis 2 | Version 1.9, FRAPS runs |
| Elder Scrolls V: Skyrim | Version 1.2.14.0, FRAPS runs |
| World of Warcraft | Version 4.3.0.150.50, FRAPS runs |
Especially in the early stages of a product’s life cycle, synthetic benchmarks give us a glimpse at how well drivers are coming along, as vendors almost always devote lots of time optimizing for those tests. But gamers don’t play synthetics, making real-world metrics much more critical to us enthusiasts. Let’s start with Battlefield 3, one of the most graphically-impressive titles of 2011:
With ultra detail enabled, the Radeon HD 7970 blows past the Radeon HD 6970 and GeForce GTX 580, nipping at the heels of the GeForce GTX 590. It provides smooth Eyefinity performance across three 1080p monitors, too. Note that the GeForce GTX 580 is simply unable to compete in that configuration, as Nvidia’s single-GPU graphics cards require SLI to facilitate at least three cumulative display outputs.
Now let’s make things more interesting by adding 4x MSAA to the mix:
The Radeon HD 7970 doesn’t do as well as the dual-GPU cards with 4xAA at 1080p, but it still manages a playable frame rate, easily surpassing the single-GPU competition.
The triple-monitor Eyefinity result looks impressive, but it’s not really playable on any of these graphics cards. The GeForce GTX 590 couldn’t run in Surround mode consistently without crashing.
The new card performs really well at 1080p, but it falters in the three-monitor configuration that so many of our readers have been asking to see us start using. Then again, the dual-GPU cards can’t muster a 30 FPS minimum, either. It looks like you’d have to reduce graphics detail across all of these cards to achieve more playable settings on a trio of displays.
Running at 1080p still isn’t a problem for the Radeon HD 7970, but it’s no surprise that 5760x1080 crawls on all of these cards.
The Elder Scrolls V: Skyrim has already secured a place for itself as one of the best games of 2011. Let’s see how these graphics cards can handle its beautifully-crafted landscapes:
The close results suggest a CPU bottleneck. Skyrim didn’t present much of a challenge for these cards at its maximum settings with 4x MSAA, so we’ll enable transparency anti-aliasing and see if anything changes.
Once again, the playing field is very tight. It’s safe to say that this title is limited by our CPU. The onlygraphics card unable to provide a minimum 30 FPS at 1080p is the Radeon HD 6970.
Batman: Arkham City has a reputation for providing unplayable frame rates with DirectX 11 features enabled (Ed.: Yeah, because it was busted), but a patch was recently released that supposedly fixes the problems encountered on 64-bit Windows. We thought we’d give it a try:
The Radeon HD 7970 delivers amazing performance relative to the rest of the pack at 1080p, and it almost catches the GeForce GTX 590 at 5760x1080. But the minimum frame rates are terrible across the board. It looks like the patch didn’t solve all of the bugs in DirectX 11 mode. We’ve given this one a couple of chances now—it’s safe to say it’ll likely see its way out of our benchmark suite in favor of something a little more stable.
Let’s add 4x MSAA, just to see what happens (and because we enjoy the pain; meow).
The Radeon HD 7970 destroys its competition at 1080p. But 5760x1080 is much harder on the card, and it remains behind the GeForce GTX 590.
Metro 2033 might not be the newest title available—in fact it’s downright old by most gaming standards—but it’s one of the most brutal on graphics hardware, with a DirectCompute-based depth of field filter selectable in DirectX 11 mode. Let’s try High details using DirectX 9 first:
AMD’s new übercard leads the pack at 1080p, and it sits just behind the dual-GPU cards at 5760x1080. Now we’ll pour on the DirectX 11, DoF, and anti-aliasing syrup:
Well that’s disappointing, isn’t it? Minimum and average frame rates drop to the floor at 1080p. While the Radeon HD 7970 holds up well compared to the competition, 5760x1080 can only provide a pyrrhic win for the new Radeon.
Let’s say that the Radeon HD 7970 has the potential to be an amazing performer. Would it still be worth $550 if its maximum power load were enough to cause blackouts at Candlestick Park during a 49ers game? Fortunately, we don’t have to speculate.
Surprisingly, the 7970 draws less load power than a GeForce GTX 580, while pulling less at idle than a Radeon HD 6970. AMD’s power management advancements should pay dividends amongst our European audience, which has to pay significantly more for electricity than the North American readers.
Now it’s time to turn our attention to GPU temperatures. We should mention that the GeForce GTX 580 we’re testing with is a Gigabyte GV-N580SO-15I clocked down to reference frequencies and equipped with an aftermarket cooler.
The temperatures are right where we’d expect them to be in comparison to the Radeon HD 6970, a card with a similar TDP.
Finally, let’s have a look at the noise generated by these products. Once again, keep in mind that the GeForce GTX 580 isn’t a reference card, and its aftermarket cooler provides an advantage you’d typically have to pay extra for.
Uh-oh. That’s a significant amount of noise, which gives us our first concerning design-oriented issue seen thus far. I’m almost afraid to mention it, because when Chris Angelini railed the Radeon HD 6990 for its noise problems, he got a lot of negative feedback. But I’m not willing to bury it, so there it is.
Concerned about a possible heat sink seating issue, I took the card apart and put it back together again with fresh thermal paste. Now, AMD doesn’t recommend this because it claims the phase-changing thermal interface material it uses enables a few-degree advantage over normal thermal paste. In light of our negative results, though, we had little to lose by at least trying. In the end, my surgical procedure made no difference, and we recorded the same acoustic output playing through Battlefield 3.
Unfortunately, AMD’s time frame for this launch didn’t make testing a second card possible. However, we’ll keep our eyes peeled for a replacement and follow-up should our findings change.
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