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Tahiti – the destination for extreme graphics performance ?

We compare AMD's marketing claims to what we found during our limited initial evaluation of the AMD Radeon HD 7970, which was tested in Intel's DXX79SI motherboard fitted with their i7-3960X six-coreenthusiast class extreme CPU.

AMD's marketing statements are enclosed in quations with our analsysis of the claims based on our evaluation following each statement.

AMD has further enhanced its GPU design efficiency through the introduction of the 28nm process technology and Graphics Core Next Architecture, realizing an improvement of over 150% in performance/sq mm over the prior generation.

Our testing found that one HD7970 uses less power and runs cooler in idle and under load than two mid-range NVIDIA GPUs and approached the numbers obtained by one NVIDIA GPU.

The performance per watt is excellent also compared to a pair of older cards. Users who only have a single monitor will not be able to fully max out the performance of a high-end system based on this card in standard setting scenarios.

AMD Power Tune technology: Designed with the most advanced power management features, the AMD Radeon HD 7970 is equipped with the intelligence to convert unused power headroom into extra performance by dynamically controlling clock speeds, allowing gamers advanced performance inside of the power envelope they specify

AMD Overdrive and Power tune specifically on the HD7970 allows some significantly high overclocking potential. We only tested a 100MHz overclock however such infamous overclockers such as 'Shamino' and 'Kingpin' have achieved near double the benchmark scores from super cooling and super over clocks.

AMD Zero Core Power technology found in the AMD Radeon HD 7970 ensures that no power is wasted when the graphics card is not in use, enabling lower idle power than any other currently available graphics card. With support for AMD Crossfire technology, AMD Zero Core Power eliminates wasted power, as well as additional heat and noise from extra cards when you are not using them.

For single cards, we are not sure of the merit of Zero Core which will turn off all of the graphics logic when the system enters long idle, that is screen saver or screen sleep. Zero Core only provides benefit when the graphics is asleep not when he desktop is drawn but idle. For multiple cards, this is a much sought after feature which can save up to hundreds of watts.

The AMD Radeon HD 7970 comes natively equipped with support for PCI Express 3.0.

AMD's own 900 series and A75 series chipset platforms do not support PCI Express 3.0 Intel 6 series motherboards are PCI-E 3.0 ready such as those from Asrock., however these will be superseded by 7 series once Intel's 3rd Generation Core CPU (codenamed Ivy Bridge) CPUs are launched.

We do not see a large number of users upgrading their 2011 6 series motherboards with PCI-E 3.0 CPU and Graphics cards combined. In such scenario user might as well upgrade motherboard for additional benefits of on-board features.

To make the best use of the faster models of the 7000 series one needs to pair the AMD cards with an Intel X79 platform. AMD even recommended testing using i7-3960X in its review documentation


Discrete Digital Multi-Point (DDM) Audio: DDM Audio provides multiple independent audio streams for audio-capable displays via DisplayPort or HDMI signals.

The audio system in Windows 7 only allows one default audio device but many enabled devices. To use all six audio outputs provided by the new Radeon GPU we need to run six applications, each set to a different audio output. A particular game or software cannot use all six connected monitor audio systems as a surround sound setup.

Users who have Eyefinity multi monitor and use monitor audio can direct audio to their preferred screen. Additionally a directional feature is supported which allows the audio device to follow applications that are moved between different displays.

AMD Crossfire technology, coupled with PCI Express 3.0, will allow for unprecedented bandwidth in TriFire and QuadFire configurations.

The only platform on sale that can support PCI-E 3.0 with TriFire and QuadFire is the Intel 2nd Generation Core i7 3000 series processor and certain motherboards based X79 chipset whose BIOS incorporates PCI-E 3.0 support.

AMD claim 2x Crossfire scaling when a second card is added, 15-20fps increase for Battlefield 3 at 19x12 and 25x16 for a single HD7970 versus HD6970 and GTX580 where two cards will double the frame rate. Although we did not test Battlefield 3, we confirmed the levels of performance with other reviews versus numbers provided by AMD.

AMD Eyefinity 2.0 features all-new support for stereo 3D, universal bezel compensation, brand new display configurations and an expanded and more immersive field of view. This allows users with 2560x1600 monitors in an AMD Eyefinity 5x1 landscape configuration to achieve a horizontal resolution of 12,800 pixels, driving more than 20 million pixels of screen real estate.

Eyefinity 2.0 gives us a means to use the AMD 7900's immense processing headroom. HD7970 AKA "Tahiti XT" is designed to drive multiple monitors at high fidelity at fair frame rates. The GPU's new architecture is highly scalable. AMD claim 40fps at 7680x1600 Ultra for Battlefield 3 when two HD7970 are in Crossfire.

We have seen no results so far from AMD or independent reviews indicating what performance is possible at 12,800 horizontal resolutions. The reference card only allows four outputs and we would need to daisy chain DisplayPort monitors to use additional screens.

DisplayPort 1.2 and HDMI 1.4a: With full support for 3GHz HDMI 1.4a and DisplayPort 1.2 HBR2, the AMD Radeon HD 7970 is set to drive next generation displays at up to 4K resolution.

The display industry is gearing up to transition to 4Kx2K and 4Kx4K high resolution displays so the support for High-Speed specifications of HDMI and DP is welcome. DisplayPort 3D monitors are now supported.

3D entertainment choices with AMD HD3D technology: With the arrival of the latest in stereo 3D technology, AMD continues to deliver an enhanced visual experience on stereo 3D-capable desktops and notebooks powered by AMD Radeon graphics. The AMD Radeon HD 7970 is backed by AMD's open 3D initiative for stereo 3D gaming and Blu-ray 3D movies.

Stereoscopic 3D regardless of the vendors technology does have performance penalties involved in its display. With an AMD FX based system, AMD claim 47fps is achievable for 3D stereo gaming in Battlefield 3 at 1080p High settings with one HD7970.