NVIDIA GeForce GT 445M
The NVIDIA GeForce GT 445M is a fast mid-range laptop graphics card introduced in 2010. It is based on the GF106 core, which is related to the Fermi architecture. Therefore, it supports DirectX 11 and OpenGL 4.0. In contrast to the GTX 460M, the card only features 144 of the 192 shader cores. Depending on the configuration, the GPU is available in 128 bit DDR3 or 192 bit GDDR5 for VRAM. The performance difference between the two versions can differ significantly.
The GF106 core of the GTX 445M is related to the GF100 core of the GeFore GTX 480M and offers a maximum of 192 shaders and a 192 Bit memory bus with GDDR5. The GT 445M offers only 144 shaders and, in some variants, also a smaller memory bus with DDR3. Except for the memory controllers, the GF106 can essentially be considered a halved GF104. Therefore, the architecture is not comparable to the old GT215 (e.g., GeForce GTS 350M) or GT216 (e.g., GeForce GT 330M) cores.
Unlike the GF100, the smaller GF104, GF106 and GF108 cores were not only shortened, but also considerably modified. In contrast to the GF100, which was designed for professional applications, these latter GF10x chips target the consumer market. They feature more shaders (3x16 instead of 2x16), more texture units (8 instead of 4) and more SFUs per streaming multi-processor (SM).
As there are still only 2 warp schedulers (versus 3 shader groups), Nvidia now uses superscalar execution in order to utilize the higher amount of shaders per SM more efficiently. In other words, the shaders operate more efficiently with higher performance per core.
However, in worst case scenarios the performance can also be worse than of the GF100 and its predecessors. The ECC memory protection, which is important for professional applications, was completely omitted and the FP64 hardware shortened (only 1/3 of the shaders are FP64-capable and thereby only 1/12 of the FP32’s performance). Because of these cutbacks, the size of the SM grew only by 25% despite the higher number of shaders and larger warp schedulers with superscalar dispatch capabilities.
Due to the different shader architectures and the higher clock rates of the shader domain, the Nvidia core count cannot be directly compared to AMD cores of the Radeon 5000 series (e.g. HD 5830).
Detailed information on the GF104 architecture (and also the GF106 and GF108 by extension) can be found in the desktop GTX 460 article by Anandtech.
Because the GeForce GT 445M features the new Fermi architecture, the performance is not comparable to older chips with a similar core count. General performance heavily depends on the used memory, as DDR3 should be a bottleneck to the performance. The gaming performance is intended to be on a level with the Mobility Radeon HD 5850, assuming that the same type of graphics memory is used. In our tests, a DDR3 GeForce GT 445M was on average 14% faster than a DDR3 Radeon HD 5850 with DDR3. Furthermore, the the Fermi based chips offer a higher Tessellation performance than DX11 chips of the Radeon HD 5000 series. See below for our detailed benchmark values and gaming tests.
A novel feature of the GF104/106/108 chips is the support for Bitstream HD Audio output via HDMI for Blu-ray playback. Similar the Radeon HD 5730, the GT 445M can transfer Dolby True HD and DTS-HD bitstream without quality loss to a HiFi receiver.
The GT445M offers the PureVideo HD technology for video decoding. The included Video Processor 4 (VP4) supports feature set C and is able to fully decode MPEG-1, MPEG-2, MPEG-4 Part 2 (MPEG-4 ASP - e.g., DivX or Xvid), VC-1/WMV9, and H.264 (VLD, IDCT, Motion Compensation, and Deblocking). In our tests, a 1080p H.264 encoded movie was playing fluently at very low CPU utilization (about 1%). A 1080p Youtube Flash video stressed the CPU only at 4%.
Furthermore, the GPU is able to decode two 1080p streams simultaneously (e.g., for Blu-Ray Picture-in-Picture).
Through CUDA, OpenCL and DirectCompute 2.1 support, the GeForce GT 445M can be of help in general calculations. For example, the stream processor can encode videos considerably faster than can a modern CPU. Furthermore, physics calculations can be done by the GPU using PhysX. Certain games, such as Mafia 2 or Metro 2033, natively support this feature.
According to Nvidia, support for 3D Vision on the GT 445M is also new. It enables the laptop to send 3D content (3D games, 3D Web Streaming, 3D photos, 3D Blu-Rays) to a built-in 3D-enabled screen or an external 3D TV if supported by the laptop manufacturer.
According to rumors, the power consumption of the GeForce GT 445M should be about 45 Watt TDP if including the MXM board and memory, which is about the level of a Mobility Radeon HD 5830. If idle, the chip is clocked at 50/100 MHz (chip/shader) in 2D mode and 200/400 in 3D mode for power-saving purposes. Furthermore, the 400M series supports Optimus to automatically switch between the integrated graphics card from Intel and the Nvidia GPU. Most notebooks include this feature, but its implementation is completely dependent on the notebook manufacturer.
GeForce GT 400M Series
|Pipelines||144 - unified|
|Core Speed||590 MHz|
|Shader Speed||1180 MHz|
|Memory Speed||1250 MHz|
|Memory Bus Width||192 / 128 Bit|
|Memory Type||DDR3, GDDR5|
|API||DirectX 11, Shader 5.0|
|Features||Optimus Support, PureVideo HD VP4, 3D Vision, Bitstream HD Audio, CUDA, DirectCompute, OpenCL, OpenGL 4.0, DirectX 11|
|Date of Announcement||03.09.2010|
|Link to Manufacturer Page||http://www.nvidia.com/object/product-gef...|