CHIP DESIGNER AMD has released the Radeon HD 7970 based on its Tahiti GPU chip.
AMD's Radeon HD 7970 is the first graphics board design based on its 28nm Southern Islands Tahiti GPU. The chip, which AMD claims has 4.3bn transistors, has been significantly changed from the previous Northern Islands generation Cayman Radeon HD 6970, has more on-chip cache and the firm claims it has greater overclocking headroom.
AMD's Tahiti architecture has up to 32 compute units with 32 colour render output units. A 384-bit memory interface results in memory bandwidth of over 264GB/s, with the firm spending a great deal of effort telling journalists about the need for 3GB GDDR5 memory by the latest triple-A games titles.
The firm's Radeon HD 7970 reference graphics board design has 2,048 stream processors, 3GB of GDDR5 memory, one DVI port, an HDMI port and two mini-Displayport outputs supporting a total of six displays. This power hungry graphics card has one six-pin and one eight-pin power connectors.
Listening to AMD's spiel there's no doubt that the firm is positioning the Radeon HD 7970 as a significant step beyond Nvidia's Geforce GTX 580. Internal "reviewer's documents" circulated to journalists suggest the firm is seeing between 70 to 90 per cent increase in performance over its previous generation Radeon HD 6970 in games running at 2550x1600, though as usual it is best to take such figures with a pinch of salt.
Like all chip vendors, AMD didn't waste time to extol the virtues of a process node shrink. The firm not only claimed that the 28nm process node allows a 3W idle power draw by its chips, but that through its Powertune software users can automatically receive 33 per cent overclocks.
AMD told journalists it wouldn't be limiting board vendors by prescribing clock speeds and the ability to slap intricate cooling units onto the boards. While that sounds great, browsing through the current Radeon HD 6970 boards on sale, it looks like few board vendors bothered to do much more than slap a sticker onto AMD"s reference cooler.
TSMC is the wafer baker for AMD's 28nm chip. Traditionally AMD prefers to release chips made using a new process node on mainstream boards, but the firm wouldn't explain to journalists why it will have only ultra high-end 28nm parts from the outset. However, with TSMC becoming busier punching out Apple's A6 chips, perhaps AMD's relatively low-volume discrete graphics chips had to take a back seat.
AMD is pricing Radeon HD 7970 boards around £450 at launch, a hefty £200 premium over its current single-GPU range topper. At that price it really has to be trying to embarrass Nvidia's Geforce GTX 590 rather than show up the significantly less expensive single-GPU boards from either AMD or Nvidia. µ