ATI Radeon HD 5970 2GB: The World's Fastest Graphics Card

The Making Of A Radeon HD 5970

As with the Radeon HD 4870 X2 and Nvidia’s second-generation GeForce GTX 295, ATI’s Radeon HD 5970 populates a single PCB. It consists of two 2.15 billion transistor Cypress GPUs with 1GB of GDDR5 memory each, joined by a 48-lane PLX PCI Express bridge. The bridge is, for the most part, the same one seen on last-generation’s Radeon HD 4870 X2. However, it has been updated for PCI Express 2.1, an incremental and non-performance-related evolution.

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Header Cell - Column 0 Radeon HD 5970Radeon HD 5870Radeon HD 5850
Total Transistors4.3 billion2.15 billion2.15 billion
Shader Processors2 x 1,6001,6001,440
Engine Clock Rate725 MHz850 MHz725 MHz
Memory Clock Rate1,000 MHz1,200 MHz1,000 MHz
Memory Bandwidth2 x 128 GB/s153.6 GB/s128 GB/s
Texture Units2 x 808072
Texture Fillrate116 GTexel/s68 GTexel/s52.2 GTexel/s
ROPs2 x 323232
Pixel Fillrate46.4 GPixel/s27.2 GPixel/s23.2 GPixel/s
Compute Performance4.64 TFLOPs2.72 TFLOPs2.09 TFLOPs
Maximum Board Power294W188W170W
Idle Board Power42W27W27W

Each of the two graphics processors is fully-featured, with 1,600 shader processors (ALUs), 80 texture units, 32 ROPs, and 1GB of attached GDDR5 memory on a 256-bit bus. What is changed are the core and memory clocks. The pair of Cypress chips runs at 725 MHz and the memory at 1 GHz. Thus, at stock clocks, we’d expect the Radeon HD 5970 to be the fastest single discrete card in ATI’s stable, but slower than two Radeon HD 5870s in CrossFire.

But the shipping clocks don’t tell the whole story, according to ATI.

Why Not Go All-Out?

Much of the board’s length can be attributed to the onboard power circuitry needed to drive the two Cypress GPUs. Here’s where many of the design decisions behind this card were actually made.

For example, ATI reduced the voltages it used and correspondingly dropped the 5970’s clock rates to Radeon HD 5850 levels. This was done to keep maximum board power to 294W—under the defined 300W PCI-SIG electromechanical specification, delivered through the physical slot (75W), one six-pin auxiliary connection (another 75W), and an eight-pin auxiliary connector (150W). Pushing Radeon HD 5870 frequencies (850 MHz core/1,200 MHz memory) would have pushed max. board power closer to 375-400W and immediately cut out a segment of enthusiasts who don’t have twin eight-pin auxiliary power connectors on their power supplies.

However, ATI says the Radeon HD 5970 was designed to run at those clock rates. It features specially-screened low-leakage ASICs that run cooler than higher-leakage parts. It employs 5 Gb/s GDDR5 memory actually rated for 1,250 MHz. And perhaps most important, its vapor chamber-based cooling solution is designed with enough capacity to dissipate as much as 400W.

The only missing piece is an official voltage tweaking utility. In an unprecedented move by a GPU vendor, ATI went so far as to provide us with such a utility—a reference app—to give us access to those elevated settings. According to the rep who briefed us, third-party board vendors will bundle their own voltage apps along with hardware so that those with capable-enough PSUs will get the chance to push the hardware a little further—at least to 5870 levels, we’re hoping.

That’s A Huge Board

Those of you who thought the Radeon HD 5870 was already “healthy”-sized, this 5970 is even larger—an inch longer, to be exact. Despite the increase in length, the board’s exterior isn’t much different from what you saw on the Radeon HD 5870—the same fully-shrouded red/black motif with faux rear-vents are still in effect. Because ATI kept power down under 300W, it gets away with one six-pin and one eight-pin auxiliary connector on the board’s top-edge. There’s a single CrossFire connector, should the holiday season treat you well and you want to spend $1,200 on graphics cards.

Perhaps most notable is the rear I/O bracket. Gone is the HDMI output connector (you’d have to be crazy to tie this card into an HTPC). Instead, ATI exposes two dual-link DVI outputs and a single mini-DisplayPort output. Thus, Eyefinity is still viable here, right up to 3 x 2560x1600.

ATI uses the space freed up by the smaller DisplayPort and missing HDMI outputs for a full-length exhaust vent. While there’s ventilation all along the top of the board, most of the card’s heated air exits the back. In contrast, the Radeon HD 5870 is far guiltier of re-circulating hot air.

Chris Angelini
Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.
  • cyberkuberiah
    today's a great day for graphics , as the bar's been raised again !
  • IzzyCraft
    bawhaha i was waiting for this
    5970 picture of it in size comparison is priceless to me it's freaking huge card.

    But really how are they going to get 2 chips for 5970 when they can't even get 1 for 5870 :)
  • notty22
    Wonder if this would get the same framerates as a 5870 in a AMD 965 system ?
  • In your face Gt240 =P
  • I'm getting more concerned with Nvidia these days. They keep playing with these low-end cards and haven't made anything all that great in almost a year. Hopefully Fermi doesn't turn into Itanic II.
  • amdgamer666
    Sweet, another amazing card to drool at, too bad I can't afford it. Thanks for including CF'ed 5870's, that's what I wanted to compare it to the most. The release seems to coincide with the driver update. Everybody make sure to update your drivers to 9.11 :)
    Also, because 9.11 is out, you can also try out Adobe's Flash 10.1 prelease to try out GPU-accelerated flash
    Exciting times
  • commodore64
    Wooww...4.3 billion transistors, low idle power, it's pricey but this baby has lots of potential :)

    I think ATI driven NVIDIA into a corner this time, i love the competition :)
  • christop
    Sweet but can't see spending 600 on a card...
  • 7amood
    commodore64i love the competitionThere is no competition yet >_< prices are way up there!!!
  • Honis
    Good article!

    I'll wait for a price drop since there are 0 DX 11 games out currently. Hope this forces further drops in the 4870s.