AMD Radeon HD 7990 6GB Review
Written by
Harry Butler
April 24, 2013 | 05:01
Tags: #7990 #hd-7990 #hd-7990-review
Companies: #amd
1 — AMD Radeon HD 7990 6GB Review2 — Test Setup3 — Radeon HD 7990 6GB — Battlefield 3 Performance4 — Radeon HD 7990 6GB — Bioshock Infinite Performance5 — Radeon HD 7990 6GB — Crysis 3 Performance6 — Radeon HD 7990 6GB — Skyrim Performance7 — Radeon HD 7990 6GB — The Witcher 2 Performance8 — AMD Radeon HD 7990 6GB — Unigine Heaven 3.0 Benchmark9 — Radeon HD 7990 6GB — Power and Thermals10 — Radeon HD 7990 6GB — Overclocking11 — Radeon HD 7990 6GB — Performance Analysis12 — Radeon HD 7990 6GB — Conclusion
Manufacturer: AMD
UK Price (as reviewed): MSRP £860 (inc. VAT)
US Price (as reviewed): MSRP $999 (ex. Tax)
When AMD hinted that it would be focussing on adding new SKUs to its product line-up in 2013 rather than replacing its current South Islands GPU architecture, we strongly suspected the arrival of the long awaited dual-GPU HD 7990 was on the cards. In fact, a number of AMD’s partners couldn’t wait this long; in the past we’ve already looked at Club 3D’s triple slot 7990 and the Asus Ares 2, both of which featured a pair of AMD’s top-end Tahiti XT GPUs in CrossFire on a single PCB. While those humongous, exotic-cooler equipped cards might have been AMD’s illegitimate children (to the Night’s Watch with them!), today sees the legitimisation of the 7990 SKU with an official AMD PCB, cooler design and set clock speeds.
Click to enlarge — A pair of Tahiti XT GPUs on a single 12in long, dual slot card
The pair of GPUs at the heart of the 7990 are identical to that of the Tahiti XT GPU we first encountered way back in December 2011, although AMD has re-named the chips Malta for the multi-GPU SKU.
This means they’re still built on the 28nm production process and South Islands architecture, with each offering the maximum of 2,048 stream processors. These are sub-divided between 32 compute units (AMD refers to them as GCNs), which are then further divided between four SIMD (single instruction, multiple data) engines of 16 stream processors each. Using the same GPU as the HD 7970 also means that each GPU boasts 32 ROPs and has access to a quartet of 64-bit memory controllers for a combined 2 x 384-bit memory interface with which to communicate with the 6GB of on-board (3GB per GPU) of GDDR5.
Put the two Malta GPUs together and you’re left with an 8.6 billion transistor 4,096 stream processor, pixel stomping beast, but AMD has made a couple of compromises to keep the heat (and power consumption) down. Whereas most HD 7970s now on sale will be the 1,050MHz core frequency GHz editions, the HD 7990’s GPUs run at 1GHz. The 7990’s 1.5GHz (6GHz effective) memory frequency matches that of the 7970 GHz Edition though, and means the card packs 2 x 288GB/sec of memory bandwidth (as with all multi-GPU cards, each GPU only has access to its own memory pool).
Click to enlarge — Beneath the shroud is a huge pair of heatsinks
While the specs aren’t too unsurprising, AMD’s ability to cram both GPUs, with a 1GHz core frequency, into a dual-slot card is seriously impressive. What’s more, it requires just a pair of 8-pin PCI-E power connectors to run. In comparison, the Club 3D 7990 we looked at in December ran at a core frequency of 925MHz, required three 8-pin power connectors and used an enormous triple-slot cooler. Asus’ Ares 2 didn’t compromise on frequency, running its pair of Tahiti XTs at 1,050MHz but also needed a trio of 8-pin power connectors, not to mention a dual-waterblock water cooler to keep temperatures under control.
Click to enlarge — The HD 7990 6GB boasts five mini DisplayPort connectors
The official HD 7990 is a much more subtle beast (if you can call a 12in/305mm card subtle) and finished in AMD’s red and black livery looks suitably smart.
The card is dominated by a trio of 80mm down-draft fans that blow air down through an enormous 8-heatpipe equipped heatsink that covers almost the entire area of the PCB. Beneath the heatsink is a further ridged aluminium plate that covers power circuitry and memory modules, with a back-plate cooling the memory modules on the cards under-side. It’s all encased in a plastic shroud that’s perforated on all sides to allow hot air to be exhausted on all sides. This will mean a significant amount of the card’s 375W TDP of heat will be deposited into your case, so needless to say decent ventilation is key. The fact that AMD has crammed a pair of its biggest GPUs onto a single PCB, dual-slot card remains a highly impressive feat though, and the engineers behind it should feel suitably pleased with themselves.
In another change from the rest of the 7-series, AMD has chosen to fit the HD 7990 with five display outputs rather than the usual four. However, it’s dropped HDMI in favour of Dual Link-DVI and a quartet of mini-DisplayPort connectors.
Click to enlarge — AMD’s PCB designers have excelled themselves by cramming everything onto a standard height, 12in PCB
While its specs and existence aren’t too surprising, the HD 7990’s price may catch some off guard. When we looked at Club 3D’s model last year it was selling for around £700, whilst a pair of HD 7970 GHz Editions will currently set you back around £660. In comparison, AMD has set an asking price of £860 for the HD 7990 6GB, seeing it topple even Nvidia’s GTX Titan as the current most expensive GPU on the market. This price does include AMD’s opulent Never Settle 8-game bundle, but a £200 premium for placing two GPUs onto a single PCB goes well beyond Nvidia’s pricing of the GTX 690 last year. Can the HD 7990 justify its price tag, and earn the big gold belt of Fastest Card In The World™? Let’s hit the benchmarks and find out.
1 — AMD Radeon HD 7990 6GB Review2 — Test Setup3 — Radeon HD 7990 6GB — Battlefield 3 Performance4 — Radeon HD 7990 6GB — Bioshock Infinite Performance5 — Radeon HD 7990 6GB — Crysis 3 Performance6 — Radeon HD 7990 6GB — Skyrim Performance7 — Radeon HD 7990 6GB — The Witcher 2 Performance8 — AMD Radeon HD 7990 6GB — Unigine Heaven 3.
0 Benchmark9 — Radeon HD 7990 6GB — Power and Thermals10 — Radeon HD 7990 6GB — Overclocking11 — Radeon HD 7990 6GB — Performance Analysis12 — Radeon HD 7990 6GB — Conclusion
AMD Radeon HD 7990 Review
AMD claims the AMD Radeon HD 7990, codenamed “Malta”, is the fastest graphics card, and its specs certainly support this claim. It’s a two-GPU graphics adaptor, which means it uses two separate graphics chips that work in unison to provide the graphics. In this case, the two GPUs are Radeon HD 7970s running at a base clock speed of 950MHz and a boost clock speed of 1GHz. It also has a very large 6GB memory capacity and that GDDR5 RAM runs at a clock speed of 1.5GHz.
With all this technology on one board, the card is understandably long. In fact, it’s a mammoth 300mm long, so make sure your case can accommodate it before you buy. It has two 8-pin power connectors, a TDP of 375W and will draw around 50% more than that when running at peak performance.
If you’re not sure if your PSU will handle this card, it probably won’t.
The HD 7990 is both huge and power-hungry, as you’d expect for a dual GPU card
We tested the Radeon HD 7990 with Dirt Showdown at a resolution of 1,920×1,080 and 4x anti-aliasing at Ultra quality and it produced a stunning frame rate of 106.7fps. This is faster than the Nvidia GTX Titan’s frame rate of 91.1fps, which was scored under the same conditions.
The AMD Radeon HD 7990 also scored highly in our Crysis 2 test, producing an exceptional 60.2fps at a resolution of 1,920×1,080 and Ultra quality. The GTX Titan produced an average frame rate of 49.6fps in the same test.
With higher resolution monitors now available, we were keen to see how the Radeon HD 7990 would perform at resolutions higher than Full HD, so we conducted the same tests at a resolution of 2,560×1,440. We weren’t disappointed, as the Radeon HD 7990 produced an average frame rate of 60.3fps in Crysis 2 and 104.
9fps in Dirt Showdown, which means that a drop in performance, if there is a drop in performance, is negligible.
Indeed, AMD claims the Radeon HD 7990 is well suited to very high resolution displays, such as the new 3,840×2,160-resolution “4K” displays. Sadly, we’re unable to test the Radeon HD 7990 at these super-high resolutions, but we’re sure it’ll cope.
It certainly coped well when playing Crysis 2 and Dirt Showdown at a resolution of 5,760×1,080 over three screens in Eyefinity mode. At Ultra quality and with 4x anti-aliasing, the HD 7990 produced a stunning frame rate of 90.2fps. Reducing Dirt Showdown’s graphics quality to Medium produced an average frame rate of 112fps and reducing it even further to Ultra Low produced 156.9fps. With Crysis 2, it produced 39.6fps at Ultra quality. This is much faster and smoother than the frame rate produced by the GTX Titan when running Crysis 2 in Nvidia’s Surround multi-monitor mode, as the Titan produced just 24.6fps. Reducing the graphics quality to Extreme allowed a much smoother average frame rate of 59fps.
AMD claims the Radeon HD 7990 is quieter than the GTX Titan, a card that is impressively quiet given its great performance. To produce these low sound levels, the AMD reference design uses a large heatsink and three fans to cool the board. Although the Radeon HD 7990 is quiet, and was pretty much silent when we just used the Windows desktop, it sounds like a colony of crickets when the fan speed increases. The sound isn’t so horrid that we’d rather turn off our PC and read a book instead, but it is irritating.
The Radeon HD 7990 is certainly expensive, but it’s also the fastest graphics card we’ve seen. Multi-GPU graphics cards can sometimes have issues with drivers, and you may therefore prefer a single GPU card such as the excellent GTX Titan. If you demand the fastest graphics card at this moment in time, however, you should buy the Radeon HD 7990.
Basic Specifications |
|
|---|---|
| Price | £856 |
| Rating | ***** |
| Details | www. amd.com |
| Award | Ultimate |
| Interface | PCI Express x16 3.0 |
| Crossfire/SLI | CrossFire |
| Slots taken up | 2 |
| Brand | AMD |
| Graphics Processor | AMD Radeon HD 7970 x2 |
| Memory | 6144MB GDDR5 |
| Memory interface | 384-bit |
| GPU clock speed | 950MHz |
| Memory speed | 1.50GHz |
| Card length | 300mm |
Features |
|
| Architecture | 4,096 stream processors |
| Anti aliasing | 16x |
| Anisotropic filtering | 16x |
Connectors |
|
| DVI outputs | 1 |
| VGA outputs | 0 |
| S-video output | no |
| S-Video input | no |
| Composite outputs | no |
| Composite inputs | no |
| Component outputs | no |
| HDMI outputs | 0 |
| Power leads required | 2x 8-pin PCI Express |
Extras |
|
| Accessories | none |
| Software included | Bioshock Infinite, Far Cry 3 Blood Dragon, Crysis 3 |
Buying Information |
|
| Warranty | one year RTB |
| Price | £856 |
| Supplier | http://www.
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