ATI Mobility Radeon HD 5870 Crossfire

ATI Mobility Radeon HD 5870 Crossfire

The ATI Mobility Radeon HD 5870 Crossfire (CF) (or ATI Mobility Radeon HD5870 X2) is a high-end DirectX 11 capable graphics solution for notebooks by AMD. It consists of two single Mobility HD5870 cards bound together using Crossfire (similar to Nvidia's SLI). In this setup, alternate frame rendering (AFR) is the most common rendering technique. At the time of announcement (Jan 2010), the 5870 CF paired with GDDR5 memory was the fastest laptop graphics solution available. Technically, the chip is based on the desktop Radeon HD 5770 (RV840), but with a slower clock rate.

Because each card renders a different frame, the Crossfire solution may suffer from micro stuttering at the 20-30 FPS range as there are irregular delays between sequential frames. Therefore, the Crossfire HD 5870 may need higher framerates for fluent gameplay.

The memory interface of the Mobility 5870 is composed of two 64 bit wide controllers leading to a 128 bit memory bus that can access up to 1024 MB of DDR3 or GDDR5 memory. If DDR3 is used by the laptop vendor, then the graphics performance will suffer noticeably.

The HD5870 CF offers 2x800 MADD cores (called Stream Processors) which are grouped in 2x160 5-dimensional groups. The cores support DirectX 11 functions in hardware (Tessellation, OIT, Post-Processing, Shadows, HDR Texture Compression). Furthermore, 16 ROPs, 40 TMUs, and 40 TAUs can be found on each chip. All in all, 2x1040 Million transistors offer a theoretic computation power of up to 2x1.12 TFLOPS. 

According to AMD, the HD 5000 series was also improved with regards to general computing. For comparison, the HD 4000 series received no such optimizations. Therefore, the performance of ATI stream, OpenCL, and DirectCompute 11 applications should be noticably better with the Mobility 5870 Crossfire.

Compared to the previous generation (in this case the Mobility Radeon HD 4870 X2), the HD5870 X2 should be about 20% faster according to AMD. This is only valid for a GDDR5 version of the HD5870 (otherwise the memory bus would be the bottle neck). The gaming performance of the CF solution should be sufficient for all current games (2009-2010) in high resolution and high detail settings with some AA enabled. Compared to a GeForce GTX 285M SLI, the 5870 CF should be faster (altough the SLI driver support by Nvidia has been known to be a bit more superior).

The Mobility Radeon HD 5000 series includes an improved video processor (UVD2) to decode HD videos with the graphics card. The new version is able to decode two HD streams simultaneously (e.g., for Blu-Ray picture in picture) if the graphics card offers enough memory bandwidth (possibly only versions with GDDR5). Since Flash 10.1 Beta, the 5000 series has also been able to help accelerate Flash HD videos (like YouTube).

A special feature of the HD 5000 series is its ability to transmit HD audio formats (like Dolby True HD or DTS HD Master Audio) with up to 8 channels and 192 kHz / 24 Bit over HDMI 1.3a.

As the desktop HD 5000 series, the Mobility HD 5870 also supports Eyefinity to connect up to 6 monitors to the graphics chip. Of course, this depends on how many monitor outputs the laptop vendor adds to the notebook and how they are wired. Most laptops will support up to three screens simultaneously (one internal and two external).

Due to the high power consumption of the Mobility Radeon HD 5870 CF, it is only suited for large laptops with good (and possibly loud) cooling solutions. According to AMD, the performance per watt ratio (same power consumption, better performance) and the idle power consumption have been improved (thanks to Memory Clock Scaling and Clock Gating). Furthermore, the chip does support PowerXpress (with an AMD chipset) and Switchable Graphics (Intel) to switch between the dedicated and chipset / integrated graphics card.

Compared to desktop graphics cards, the Mobility Radeon HD 5870 CF should perform somewhere between a Radeon HD 5750 and 5770 in Crossfire mode based on the shader count of the 5770 and the clock rate of 5750.

Mobility Radeon HD 5800 Series
Mobility Radeon HD 5870 Crossfire 1600 @ 700 MHz128 Bit @ 1000 MHz
Mobility Radeon HD 5870 (compare) 800 @ 700 MHz128 Bit @ 1000 MHz
Mobility Radeon HD 5850 (compare) 800 @ 625 MHz128 Bit @ 2000 MHz
Mobility Radeon HD 5830 (compare) 800 @ 500 MHz128 Bit @ 800 MHz
ArchitectureTerascale 2
Pipelines1600 - unified
Core Speed700 MHz
Memory Speed1000 MHz
Memory Bus Width128 Bit
Memory TypeDDR3, GDDR3, GDDR5
Max. Amount of Memory2x1024 MB
Shared Memoryno
DirectXDirectX 11, Shader 5.0
technology40 nm
FeaturesEyefinity (up to 6 displays), HD Audio (Dolby True HD, DTS HD), HDMI 1.3a, Avivo HD (UVD2.2)
Notebook Sizelarge
Date of Announcement07.01.2010
Information2x1.12 TFLOPS


3DMark Vantage
P Result 1280x1024 +
P GPU no PhysX 1280x1024 +
3DMark 06 Standard 1280x1024 +
Unigine Heaven 2.1 - high, Tesselation (normal), DirectX11 1280x1024
42.5 fps (19%)
SPECviewperf 11
Siemens NX 1920x1080 +
Tcvis 1920x1080 +
SolidWorks 1920x1080 +
Pro/ENGINEER 1920x1080 +
Maya 1920x1080 +
Lightwave 1920x1080 +
Ensight 1920x1080 +
Catia 1920x1080 +
Cinebench R10 Shading 32Bit +
Cinebench R11.5 OpenGL 64Bit +
- Range of benchmark values for this graphics card
- Average benchmark values for this graphics card
* Smaller numbers mean a higher performance

Game Benchmarks

The following benchmarks stem from our benchmarks of review laptops. The performance depends on the used graphics memory, clock rate, processor, system settings, drivers, and operating systems. So the results don't have to be representative for all laptops with this GPU. For detailed information on the benchmark results, click on the fps number.

Fifa 11

Fifa 11

low 800x600
250.4  fps    + Compare
med. 1024x768
167.3  fps    + Compare
high 1360x768
83.9  fps    + Compare
ultra 1920x1080
58.7  fps    + Compare
» With all tested laptops playable in detail settings ultra.
Mafia 2

Mafia 2

low 800x600
56.7  fps    + Compare
med. 1024x768
56.6  fps    + Compare
high 1360x768
56.9  fps    + Compare
ultra 1920x1080
56.8  fps    + Compare
» With all tested laptops playable in detail settings ultra.
low 1024x768
158.8  fps    + Compare
med. 1360x768
57.9  fps    + Compare
high 1360x768
57.9  fps    + Compare
ultra 1920x1080
51.2  fps    + Compare
» With all tested laptops playable in detail settings ultra.
low 800x600
87.5 fps  fps    + Compare
med. 1360x768
79.9 fps  fps    + Compare
high 1600x900
52.7 fps  fps    + Compare
ultra 1920x1080
18 fps  fps    + Compare
» With all tested laptops playable in detail settings high.
low 1024x768
113.9 fps  fps    + Compare
med. 1366x768
103.9 fps  fps    + Compare
high 1366x768
96.8 fps  fps    + Compare
ultra 1920x1080
57.7 fps  fps    + Compare
» With all tested laptops playable in detail settings ultra.
low 800x600
163.3 fps  fps    + Compare
med. 1024x768
97.3 fps  fps    + Compare