NVIDIA GeForce GTX 460M vs NVIDIA GeForce GTX 485M
NVIDIA GeForce GTX 460M► remove
The NVIDIA GeForce GTX 460M is a high-end laptop graphics card released in 2010. It is based on the GF106 core as part of the Fermi architecture. As a result, the GPU supports DirectX 11 and OpenGL 4.0. In contrast to the GT 445M, which only features 144 core, the GTX 460M offers all the 192 shader cores of the GF106. The faster GTX 470M is based on the GF104 and offers even more shader cores at 288.
The GF106 core of the GTX 460M is related to the GF100 core of the GeFore GTX 480M and offers 192 shaders and a 192 Bit memory bus for GDDR5. Except for the memory controllers, the GF106 can basically 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 have not only been reduced in size, but have also been considerably modified. In contrast to the GF100, which was designed for professional applications, these chips target the consumer market. They feature more shaders (3x16 instead of 2x16), more texture units (8 instead of 4) and SFUs per streaming multi-processor (SM). As there are still only 2 warp schedulers (versus 3 shader groups), Nvidia now uses superscalar execution to use the higher amount of shaders per SM more efficiently. In theory, the shaders can thereby be utilized more effectively and the performance per core can be improved.
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 shader are FP64-capable and therewith 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 rate of the shader domain, the core count of the GTX 460M cannot be directly compared to AMD cores of the Radeon 5000 series (e.g. HD 5850).
Detailed information on the GF104 architecture (and by extension also the GF106 and GF108) can be found in the desktop GTX 460 article by Anandtech.
Because the GeForce GTX 460M features a new architecture, the performance is not comparable to older chips with a similar core count. In contrast to the Radeon HD 5850, which could optionally use DDR3 memory, the 192 Bit memory bus of the GTX 460M is combined with GDDR5. Furthermore, the Fermi based chips offer a higher Tessellation performance than DX11 chips of the Radeon HD 5000 series.
We ran a set of benchmarks on an early pre-sample of a Toshiba Qosmio X500 with a 740QM CPU. In the synthetic benchmarks, the GTX 460M was on par with the DDR3 based Mobility Radeon HD 5850. In actual game benchmarks and tests, the performance was better than a HD 5850 with GDDR5 on average. In some cases (e.g., Unigine Heaven 2.1 and Dirt 2 Demo), the card even beat a Mobility Radeon HD 5870. On average, the GTX 480M was about 8-18% faster. The detailed benchmark and gaming results (including charts) can be found below.
A novelty of the GF104/106/108 chips is the support for Bitstream HD Audio (Blu-Ray) output via HDMI. Similar to the Radeon HD 5850, the GTX 460M can transfer Dolby True HD and DTS-HD bitstream without quality loss to a HiFi receiver.
The GTX460M offers PureVideo HD technology for video decoding. The included Video Processor 4 (VP4) supports feature set C and therefore the GPU 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). The X500 notebook tester was able to decode the VC-1 encoded Elephants Dream video with about 3-6% CPU load (according to the task manager). The H.264 coded Big Buck Bunny video was played back with 1-3% CPU load (both 1080p videos).
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 GTX 460M can be of use in general calculations. For example, the stream processor can encode videos considerably faster than can many modern CPUs. Furthermore, physics calculations can be done by the GPU using PhysX if supported (e.g., Mafia 2 or Metro 2033). For example, the X500’s GPU ran Fluidmark more than 3x faster than its CPU (36 versus 11 fps) in our tests.
According to Nvidia, 3D Vision is supported on the GTX graphics cards. 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.
Unofficially, the power consumption of the GeForce GTX 460M should be about 72 Watt (TDP including the MXM board and memory), which is about the level of the Mobility Radeon HD 5850 - 5870. If not under load, the chip is clocked at 50/100 MHz (chip/shader) and 200/400 in 2D mode and 3D mode, respectively, to save power. Furthermore, the 400M series supports Optimus to automatically switch between the integrated graphics card from Intel and the Nvidia GPU. However, its implementation is dependent on the manufacturer. As current (2010) quad-cores don’t house an integrated GPU, we won’t see many Optimus designs with a GTX 460M GPU before the launch of Sandy Bridge in 2011.
The similarly named desktop GeForce GTX 460 is based on the GF104 chip and offers more shader cores at 336. Therefore, it is significantly faster than the GTX 460M and even the GTX 470M.
NVIDIA GeForce GTX 485M► remove
The Nvidia GeForce GTX 485M is the fastest graphics card for laptops at the time of announcement (Q1 2011). It is based on the GF104 chip and offers all 384 shader cores and the full 256 Bit memory bus. Due to the high clock rate of 575 MHz, it is significantly faster than the old GeForce GTX 480M of which it replaces. It also supports DirectX 11 and OpenGL 4.0.
Other than the GeForce GTX 480M, the 485M is no longer based on a trimmed down GF100 chip, but on the related GF104 instead. The GF104 is designed for the consumer sector and has a total of 384 cores. A number of cores may be disabled, for example the 470M with only 288 active cores.
The technology of the GF104 differs quite a bit from the GF100 chip (which was actually designed for professional use). The GF104 has more shaders (3x16 vs. 2x16), texture units (8 vs. 4) and SFUs (Special-Funciton-Units) per Streaming-Multiprocessors (SM). Nvidia now uses the superscalar architecture as there are still only two warp schedulers supporting three shader blocks. In theory, this helps to utilize the shaders more efficiently and increases the performance per core.
However, in the worst case, the performance can drop below the GF100 architecture (and its predecessors). The ECC memory protection, important in professional applications, was completely omitted and the FP64 was trimmed down (only 1/3 of the shaders are FP64-capable, only 1/12 of the FP32 performance). Because of these reductions in the GF104, the size of a SM increased only by 25% despite the higher number of shaders.
Note that it is not possible to directly compare the number of cores to the AMD Radeon graphics cards (e.g. HD 5870) or even to Nvidia's own predecessors (e.g., G92b), because shader architecture and clock rates are significantly different in the GF104 chip.
In our extensive test of the GeForce GTX 485M, we found that the GTX485M is significantly faster than the old GeForce GTX 480M (at the same TDP rating). The performance is on a level with two GeForce GTX 460M in SLI mode. Nearly all games are therefore playable in highest details and resolutions. Even demanding games like Mafia 2 or Battlefield Bad Company 2 can run fluently in 1080p with maximus detail settings. Detailed benchmarks can be found at the end of this page.
What's new compared to the GF100 is support for Bitstream transfer of HD Audio (Blu-Ray) via HDMI in the GF104 chips. Similar to the HD 5850, the GTX 485M can transmit Dolby True HD and DTS-HD via Bitstream to compatible receivers without quality loss.
For decoding HD videos, the GTX485M supports PureVideo HD. The built-in Processor 4 (VP4) handles Feature Set C. As a result, MPEG-1, MPEG-2, MPEG-4 Part 2 (MPEG-4 ASP - z.B. DivX or Xvid), VC-1/WMV9 and H.264 can be fully decoded by the graphics card (VLD, IDCT, Motion Compensation, and Deblocking). Furthermore, two streams can be simultaneously decoded in realtime, e.g. Blu-Ray Picture-in-Picture (2x1080p lt DXVAChecker). In addition, PureVideo HD indicates HDCP encoding for digital interfaces.
The shader cores (also called CUDA cores) can also be used for general computations (e.g. Video Transcoding) by using the interfaces CUDA, DirectCompute 2.1 or OpenCL. Thanks to PhysX, the 485M can also perform physics calculations.
According to Nvidia, the support for 3D Vision includes support for the recent HDMI 1.4a standard as well. If enabled by the laptop manufacturer, content such as 3D games, 3D web streaming videos, 3D pictures and 3D Blu-Ray videos can be displayed on a 3D-capable TV (via discrete 3DTV Play) or on the internal notebook 3D display.
With regards to energy demand, the GTX 485M should be on par with the GeForce GTX 480M. In other words, both graphics cards should draw about 100 Watts each when including their respective memory and MXM boards. Due to the higher performance from the 485M, the performance/power efficiency here has clearly been improved.
Compared to desktop graphics cards, the performance of the 485M should be on par with a GeForce GTX 460 768MB which features less cores but operates on higher clock rates.
|NVIDIA GeForce GTX 460M||NVIDIA GeForce GTX 485M|
|GeForce GTX 400M Series|
|192 -||384 -|
|Core||675 MHz||575 MHz|
|Shader||1350 MHz||1150 MHz|
|Memory||1250 MHz||1500 MHz|
|Bus||192 Bit||256 Bit|
|Max. Memory||1536 MB|
|DirectX||DirectX 11, 5.0||DirectX 11, 5.0|
|Technology||40 nm||40 nm|
|Features||Optimus Support, PureVideo HD VP4, 3D Vision, Bitstream HD Audio, CUDA, DirectCompute, OpenCL, OpenGL 4.0, DirectX 11, SLI Supported|