NVIDIA GeForce GTX 485M SLI vs NVIDIA GeForce GTX 485M
NVIDIA GeForce GTX 485M SLI► remove
The NVIDIA GeForce GTX 485M SLI is a high-end laptop graphics solution based on two GTX 485M graphics cards. With SLI, each card usually renders a single frame (AFR mode). Therefore, it may suffer from micro stuttering in low fps ranges of 30fps. This happens because of different timespans between two frames (e.g. irregular delays between sequential frames).
The GeForce GTX485M SLI supports the same features as a single GTX 485M card. Therefore, it supports DirectX 11 and is produced in a 40nm fabrication process at TSMC.
Unlike the GeForce GTX 480M, the 485M is no longer based on a trimmed down GF100 core, but on the GF104 core instead. The latter has been designed for the consumer sector and has 384 cores maximum if completely enabled. More information on the GF104 core can be found on the GTX 485M page.
The performance of the Nvidia GeForce GTX 485M SLI is clearly better than the GTX 480M SLI and is therefore the fastest graphics solution for laptops as of early 2011. It allows the user to play all current games in high resolutions and detail settings with Antialiasing activated. Only Metro 2033 and Crysis may stutter with high Antialiasing and maximum details. Compared to a single GTX 485M, the performance from the SLI combination should be about 40% higher on average (with high details and Antialiasing). Compared to Crossfire solutions by AMD, the Nvdia SLI drivers have the advantage as of this writing.
As the GeForce 300M series, the GeForce GTX 485M supports PureVideo HD with VideoProcessor 4 (VP4 with Feature Set C). This means that the GPU is able to fully decode HD videos in H.254, VC-1, MPEG-2, and MPEG-4 ASP. Using Flash 10.1, the graphics card can also accelerate Flash videos.
What's new in the GF104 chips compared to the GF100 (480M) is the support for Bitstream transfer of HD Audio (Blu-Ray) via HDMI. Similar to the HD 5850, the GTX 485M can transmit Dolby True HD and DTS-HD via Bitstream to compatible receivers without quality loss.
The rendering cores of the Nvidia GeForce GTX 485M can be used for general calculations using CUDA or DirectCompute. In other words, the encoding for HD videos can be done significantly faster by using the shader cores of the GPUs instead of using modern CPUs. PhysX is also supported by the mobile Fermi to calculate physics effects in supported games. Furthermore, a single GTX485M can be used to calculate PhysX while the other card can render frames in the SLI setup.
Compared to desktop GPUs, the Geforce GTX 485M SLI is most similar to two Nvidia GeForce GTX 460 cards running in an SLI configuration.
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 485M SLI||NVIDIA GeForce GTX 485M|
|GeForce GTX 400M Series|
|768 -||384 -|
|Core||575 MHz||575 MHz|
|Shader||1150 MHz||1150 MHz|
|Memory||1500 MHz||1500 MHz|
|Bus||256 Bit||256 Bit|
|Max. Memory||2x2048 MB|
|DirectX||DirectX 11, 5.0||DirectX 11, 5.0|
|Technology||40 nm||40 nm|