AMD Radeon HD 7850M vs AMD Radeon HD 7870M

AMD Radeon HD 7850M

The AMD Radeon HD 7850M is a 28nm DirectX 11 graphics card based on the GCN (Graphics Core Next) architecture. Built primarily for medium-large laptops, the graphics card is positioned in the performance category as of 2012.

The design of the Radeon 7800M series has its roots to the Cape Verde chip as found, for example, on the desktop Radeon HD 7770 with 640 1D shader cores and 40 texture units. However, the core clock of only 675 MHz is significantly lower, also in comparison with the HD 7870M (800 MHz).  As a result, the performance of the HD 7850M should be similar to the desktop HD 7750.

The 7850M is in range of Nvidias GeForce GTX 660M, offering similar or slightly better performance and a similar power consumption. Therefore, current (Spring 2012) and demanding games should run fluently in medium or high settings.

Features of the 7850M include the new UVD3 video decoder for decoding MPEG-4 AVC/H.264, VC-1, MPEG-2, Flash and now also Multi-View Codec (MVC) and MPEG-4 part 2 (DivX, xVid) HD videos directly from the AMD GPU.

The 7800M 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 7850M can directly support up to 6 connected monitors using Eyefinity Technology if Enduro is disabled.

Other features of the 7800M 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 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 7850M should be clearly below the 7870M, thanks to the lower core clock.

AMD Radeon HD 7870M

The AMD Radeon HD 7870M is a 28nm DirectX 11 graphics card based on the GCN (Graphics Core Next) architecture. Built primarily for large laptops, the graphics card is positioned in the performance category as of 2012.

The design of the Radeon 7800M series has its roots to the Cape Verde chip as found, for example, on the desktop Radeon HD 7770 with 640 1D shader cores and 40 texture units. However it has a core clock of only 800 MHz versus the 1000 MHz of the HD 7770.  As a result, general performance of the HD 7870M is expected to lie somewhere between the 7750 and 7770 desktop Radeon cards.

The 3D performance of the graphics card is clearly better than a Nvidia GeForce GTX 560M. The 3DMark 11 GPU test even is on par with a fast GeForce GTX 670M. In games a Geforce GTX 660M should offer a similar performance. AMD compared the 7870M in their announcement with the Nvidia GeForce GTX 560M that could be beaten in AvP, Batman AC, Battlefield 3, Crysis 2, Metro 2033, Skyrim and Wolfenstein rather clearly. However, keep in mind that the settings and games were chosen by AMD. 

Using OpenCL 1.2, the 10 Compute cores of the HD 7870M can be used for general computational tasks.

Features of the 7870M include the new UVD3 video decoder for decoding MPEG-4 AVC/H.264, VC-1, MPEG-2, Flash and now also Multi-View Codec (MVC) and MPEG-4 part 2 (DivX, xVid) HD videos directly from the AMD GPU.

The 7800M 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 7870M can directly support up to 6 connected monitors using Eyefinity Technology if Enduro is disabled.

Other features of the 7800M 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 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 7870M should be clearly lower than the 7970M (100W TDP) as the desktop counterparts 7750 and 7770 range between 55-80 Watt (but ACP average power). Rumors speak of 45 Watt, therefore only large laptops are suited for the 7870M.