AMD Radeon HD 8730M vs AMD Radeon HD 8790M vs AMD Radeon HD 8550G + HD 8750M Dual Graphics

AMD Radeon HD 8730M

The AMD Radeon HD 8730M (sometimes known as the ATI Mobility Radeon HD 8730) is a DirectX 11.1 graphics card for laptops. It is based on the Mars chip (28nm GCN architecture) with 384 shader cores, 24 TMUs, and 8 ROPs. The core is clocked at 650 MHz (700 MHz Boost) and can access a DDR3 VRAM (1000 MHz).

The performance of the Radeon HD 8730M is similar to the GeForce GT 640M LE. Current and demanding games (as of 2012/2013) like Far Cry 3 will run fluently in medium-low resolutions and detail settings.

The 384 shaders can be used with OpenCL 1.2 for general-purpose calculations (as 6 compute units). Compared to old TeraScale 2 chips, the GCN-based Mars architecture offers improved performance in this framework.

Features of the 8730M include video decoding via UVD3 for decoding MPEG-4 AVC/H.264, VC-1, MPEG-2, and Flash directly from the AMD GPU. Multi-View Codec (MVC) and MPEG-4 part 2 (DivX, xVid) HD videos are now compatible as well.

The 8700M 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 8730M can directly support up to 2 connected monitors using Eyefinity Technology if Enduro is disabled.

Other features of the 8700M series include ZeroCore for reducing power consumption when the display is turned off and Power Gating to power down areas of the chip that are not used. PowerTune allows automatic overclocking and underclocking of the graphics card as long as the GPU is within its TDP limit. 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.

The power consumption should be slightly below that of the old HD 7670M. As a result, the 8730M is suited for 13-inch notebooks or larger.

AMD Radeon HD 8790M

The AMD Radeon HD 8790M (sometimes known as the ATI Mobility Radeon HD 8790) is a DirectX 11.1 graphics card for laptops. It is based on the Mars chip (28nm GCN architecture) with 384 shader cores, 24 TMUs, and 8 ROPs. The core is clocked at 850 MHz (900 MHz Boost) with GDDR5 VRAM at 1125 MHz (4500 MHz effective).

The performance of the Radeon HD 8790M is similar to the Nvidia GeForce GTX 660M or GT 750M and therefore in the upper mid-range category. Most games of 2013 can be played fluently in medium or high details and the WXGA resolution of 1366 x 768 pixels.

The 384 shaders can be used with OpenCL 1.2 for general-purpose calculations (as 6 compute units). Compared to old TeraScale 2 chips, the GCN-based Mars architecture offers improved performance in this framework.

Features of the 8790M include video decoding via UVD3 for decoding MPEG-4 AVC/H.264, VC-1, MPEG-2, and Flash directly from the AMD GPU. Multi-View Codec (MVC) and MPEG-4 part 2 (DivX, xVid) HD videos are now compatible as well.

The 8700M 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 8790M can directly support up to 2 connected monitors using Eyefinity Technology if Enduro is disabled.

Other features of the 8700M series include ZeroCore for reducing power consumption when the display is turned off and Power Gating to power down areas of the chip that are not used. PowerTune allows automatic overclocking and underclocking of the graphics card as long as the GPU is within its TDP limit. 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.

The power consumption should be slightly higher than the previous 7690M chip when under load (2 Watt difference according to the desktop setup from Techreport). However, the 8790M can potentially draw less power when idle (if not disabled by Enduro). Overall, the 8790M is best suited for 15-inch notebooks or bigger.

AMD Radeon HD 8550G + HD 8750M Dual Graphics

The AMD Radeon HD 8550G + HD 8750M Dual Graphics is the combination of a integrated AMD Radeon HD 8550G APU processor graphics card and a dedicated AMD Radeon HD 8750M graphics card in CrossFire combination. It is called AMD Dual Graphics or asymmetric CrossFire and uses AFR (Alternate Frame Rendering) to render different frames on the two graphic cores. Therefore the combination also suffers from micro stuttering (different spaces between two images lead to stuttering altough the framerate is high enough for fluent gaming with only one GPU).

The performance of the Dual Graphics solution depends greatly on the driver support for the used games. In some games the performance may even degrade slightly compared to using only the dedicated graphics card. Only in best case scenarios the performance of a GT 740M is possible. Therefore, due to the micro stuttering and performance problems, Dual Graphics may impose more problems than bring performance gains. Nevertheless, even demanding games like Battlefield 4 can be played fluently in low or medium settings.

The features like PureVideo HD (UVD3) or OpenCL support are similar to the two graphics cards.

As both graphics cards are rendering frames, the power consumption is clearly higher than using only one GPU. Only notebooks 15 inches in size and above will handle the heat.