ATI Mobility Radeon HD 3870 X2

The Mobility Radeon X3870 X2 combines two Mobility Radeon 3870 graphics cards (on MXM boards) onto one laptop in Crossfire (CF) mode. Therefore, the combination has a power consumption of roughly both cards combined. While the total available VRAM has been doubled, the effective VRAM is actually half of the combined total as each card must store the same textures and data onto their own respective onboard VRAM chips.

Depending on the application, the performance of the Radeon X3870 X2 about 0-40 percent above a single Mobility HD 3870 and is even a bit above the GeForce 8800M GTX SLI solution. Most, if not all, DirectX 9 games can run fluently in high resolutions and detail settings. More demanding DirectX 10 games, such as Crysis, will only run acceptably well on medium to high detail settings with lowered resolutions.

As with all multi-GPU solutions, the HD 3870 X2 may suffer from a phenomenon known as micro stuttering. See here for an overview of the term and why it happens.

Hardware features that can be found on a single Mobility HD 3870 have been preserved in the Crossfire combination. As a result, the dual GPU setup can take advantage of Avivo HD in order to aid the CPU in decoding videos.

The power consumption of the Mobility 3870 X2 can be up to 110 Watt when including the MXM boards and VRAM chips. AMD specifies that the HD 3800 series can draw up to 33-55 Watt per card.

Manufacturer

ATI

Mobility Radeon HD 3800 Series

Mobility Radeon HD 3870 X2	640 @ 0.66 GHz	256 Bit @ 850 MHz
Mobility Radeon HD 3850	320 @ 0.58 GHz	256 Bit @ 750 MHz

Codename

M88-XT CF

Architecture

RV6xx

Pipelines

640 - unified

Core Speed

660 MHz

Memory Speed

850 MHz

Memory Bus Width

256 Bit

Memory Type

GDDR3

Shared Memory

DirectX

DirectX 10.1, Shader 4.0

Transistor Count

1332 Million

technology

55 nm

Notebook Size

large

Date of Announcement

01.09.2008

Benchmarks

3DMark Vantage
3DM Vant. Perf. total +

3DM Vant. Perf. GPU no PhysX +

3DMark 2001SE - 3DMark 2001 - Standard

min: 35136 avg: 37543 median: 37542.5 (39%) max: 39949 Points

+ 2 benchmarks and specifications + Show comparison chart

3DMark 03 - 3DMark 03 - Standard

min: 53261 avg: 55111 median: 55742 (29%) max: 56330 Points

+ 3 benchmarks and specifications + Show comparison chart

3DMark 05 - 3DMark 05 - Standard

min: 17271 avg: 19187 median: 20115 (29%) max: 20175 Points

+ 3 benchmarks and specifications + Show comparison chart

3DMark 06 3DMark 06 - Standard 1280x1024 +

Cinebench R10 Cinebench R10 Shading (32bit) +

- 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.