The beast
At first glance the card looks eerily similar to a regular Radeon HD 5870. The HD 5970 accommodates two GPUs and the associated power circuitry, of course, and this translates to a card that's plain larger.
Measuring 309mm x 110mm x 40mm (W x H x D), it is over an inch longer than the already-long HD 5870. In old money it translates to just over 12 inches, so, if you're considering such a card, please bear the length in mind.
The card's 294W TDP sounds exorbitant but is in line with the Radeon HD 4870 X2 and GeForce GTX 295 dual-GPU models.
Cooled by a vapour chamber system that's specified to handle 400W loads, the card's primed for overclocking, according to AMD.
The 2GB GDDR5 memory operates at a native 5.0Gbps - the same as HD 5870 - so there should be headroom there. The GPU ASICs, too, have been 'specially selected', intimating that the 725MHz core clock is conservative.
Further, programmable voltage regulators will let you increase board juice, within reason, monitored by hardware chips. This is why we're confident that partners will release faster-clocked models near launch day.
The card-sized cooling is barely tickled when the card is idling, but the fan does increase in volume and pitch as the twin GPUs crank out the frames. Whilst not Dustbuster-like under full load, the fan is noisy enough to hear in a high-end system that houses multiple hard drives and a 130W CPU.
The two GPUs sit side-by-side on the PCB - a move that's been adopted by NVIDIA on its GTX 295. Weighing in at 1,211g, make sure it's secured in well.
The eight-pin and six-pin PCIe arrangement of previous dual-GPU cards is carried over. Remember that a single card can consume almost 300W and a second will double that power-draw figure, so a high-quality PSU is essential.
Interestingly, AMD says there is provision for AIB partners to design in-house SKUs with two eight-pin connectors, pushing the TDP well above 300W, in order to hit higher speeds - presumably ready for NVIDIA's Fermi.
Feeling flush? A second card can be hooked-up for four-GPU, two-card CrossFireX. We'll be looking at the performance of such a setup in due course.
Radeon HD 5970 2,048MB isn't all about power. The GPU also provides eclectic multi-monitor display capability that falls under the umbrella Eyefinity term. The standard HD 5870 ships with DVI, HDMI, and mini-DisplayPort. The bigger card does away with HDMI for DVI, and that makes sense for gamers, as HDMI can be 'dongled' from DVI via an adapter.
The mini-DisplayPort connector enables the card to have the upper slot free for exhausting the heat produced by the GPUs, rather it being recirculated in the case.
Summary
A bigger, thirstier card by dint of its power, the HD 5970 fits inside the same thermal envelope as other high-powered (dual-GPU) solutions we've seen before.
