AMD Radeon HD 8970M vs AMD Radeon HD 8970M Crossfire

AMD Radeon HD 8970M

The AMD Radeon HD 8970M is a 28nm DirectX 11 graphics card based on the GCN (Graphics Core Next) architecture. Built primarily for large laptops, the advanced card is positioned near the top of the high-end category as of 2013. Its performance and feature set are similar to the HD 7970M, as the 8970M shares the same core and only features a higher maximum core clock.

The design of the Radeon 8900M series has its roots to the Pitcairn chip as found on the desktop Radeon HD 7870. The 8970M in particular is similar to its desktop Radeon HD 7870 counterpart with 1280 1D shader cores and 80 texture units, but has a core clock of only 900 MHz (boost) versus the 1000 MHz clock of the HD 7870. Compared to the HD 7970M, the 8970M shares the same base clock rate but with a 50 MHz higher Turbo clock for a 6% increase (1.01 TFLOPS vs. 1.07 TFLOPS) in raw SP calculations. As a result, general performance of the HD 8970M is somewhere between the 7850 and 7870 desktop Radeon cards.

When compared to mobile Nvidia GPUs, the HD 8970M performs significantly faster than the GeForce GTX 675M and slightly above the Nvidia GeForce GTX 680M. Therefore, almost all demanding games of 2013 will run fluently on very high details and 1080p resolution.

Features of the 8970M include the new UVD3 video decoder for decoding MPEG-4 AVC/H.264, VC-1, MPEG-2, Flash, Multi-View Codec (MVC) and MPEG-4 part 2 (DivX, xVid) HD videos directly from the AMD GPU.

The 8900M series also supports automatic graphics switching between the integrated GPU and discrete GPU. Called Enduro, the technology supersedes AMD's Dynamic Switchable Graphics and is similar to Nvidia's Optimus. Furthermore, the 8970M can directly support up to 6 connected monitors using Eyefinity Technology if Enduro is disabled.

Other features of the 8900M series include ZeroCore for reducing power consumption when the display is turned off. Power Gating, however, is not supported according to AMD. PowerTune allows automatic overclocking and underclocking of the graphics card as long as the GPU is within its TDP range. For example, the chip may be underclocked when running FurMark and OCCT, but will overclock in certain games like Lost Planet, Crysis or Resident Evil 5.

The integrated HD audio processor is able to transmit HD Audio (TrueHD or DTS Master Audio) over HDMI and DisplayPort (e.g., for Blu-Ray videos). Additionally, it now allows audio to output simultaneously and in parallel to multiple devices with the new Discrete Digital Multipoint Audio (DDMA) feature.

Power consumption of the 8970M is in the same ballpark as the GeForce GTX 680M. The subsequently large heat output suits the 8970M as an option only for large laptops or DTRs (desktop replacements) equipped with relatively powerful cooling solutions.

AMD Radeon HD 8970M Crossfire

The AMD Radeon HD 8970M Crossfire (also known as the ATI Mobility Radeon HD 8970 X2 or CrossFireX) is a combination of two high-end graphics card for big and heavy laptops. Usually, each single card renders a single frame in an alternating manner. Therefore, it may suffer from micro stuttering in low frame rates below 30 FPS due to staggering timespans between two frames (e.g., irregular delays between sequential frames).

The HD 8970M is based on the desktop HD 7870 Pitcairn chip with 1280 1D shaders and 80 texture units. The GCN (graphics core next) architecture supports DirectX11 and OpenGL 4.2. More information on the features of the single 8970M can be found on the GPU page. Compared to the 7970M, the 8970M is based on the same chip but offers an increased core clock rate by 50 MHz when in Turbo.

The Performance of two HD 8970M GPUs in Crossfire mode is similar to the GeForce GTX 680M SLI an just slightly below the GTX 780M SLI. As of 2013, however, the Crossfire solution currently suffers more from micro stuttering than Nvidia SLI solutions. Regardless, modern and demanding games like Battlefield 3 or Metro Last Light are still playable in high resolution and max. settings with anti-aliasing.

The power consumption of the CF combination is very high (2x 100 Watt) and is thus only suited for very large desktop replacement laptops.