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GeForce 900 series

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GeForce 900 Series
Release dateSeptember 2014
CodenameMaxwell
ModelsGeForce Series
  • GeForce GT Series
  • GeForce GTX Series
Cards
Mid-rangeGeForce GTX 960
High-endGeForce GTX 970
EnthusiastGeForce GTX 980
API support
DirectXDirectX 11.3 and DirectX 12(feature level 12_0)[2][3][4][5]
OpenCL1.2[1]
OpenGLOpenGL 4.5
History
PredecessorGeForce 700 series
SuccessorGeForce 1000 series

The GeForce 900 Series is a family of graphics processing units developed by Nvidia, used in desktop and laptop PCs. It serves as the high-end introduction for the Maxwell architecture (GM-codenamed chips), named after the Scottish theoretical physicist James Clerk Maxwell.

The Maxwell microarchitecture, the successor to Kepler microarchitecture, will for the first time feature an integrated ARM CPU of its own.[6] This will make Maxwell GPUs more independent from the main CPU according to Nvidia's CEO Jen-Hsun Huang.[7] Nvidia expects three major things from the Maxwell architecture: improved graphics capabilities, simplified programming as well as better energy-efficiency compared to the GeForce 700 Series and GeForce 600 Series [8]

Maxwell was announced in September 2010.[9] The first GeForce consumer-class products based on the Maxwell architecture were released in early 2014.[10] Nvidia is expected to release the Maxwell-powered Tesla accelerator cards as well as Quadro professional graphics cards based on this architecture in late 2014. Eventually, Maxwell architecture will be used for mobile application processors that belong to the Erista family of Tegra SoCs.

Architecture

Main article: Maxwell (microarchitecture)

First generation Maxwell (GM10x)

First generation Maxwell GM107/GM108 were released as GeForce GTX 745, GTX 750/750 Ti and GTX 850M/860M (GM107) and GTX 830M/840M (GM108). These new chips provide few consumer-facing additional features; Nvidia instead focused on power efficiency. Nvidia increased the amount of L2 cache from 256 KiB on GK107 to 2 MiB on GM107, reducing the memory bandwidth needed. Accordingly, Nvidia cut the memory bus from 192 bit on GK106 to 128 bit on GM107, further saving power.[11] Nvidia also changed the streaming multiprocessor design from that of Kepler (SMX), naming it SMM. The structure of the warp scheduler is inherited from Kepler, which allows each scheduler to issue up to two instructions that are independent from each other and are in order from the same warp. The layout of SMM units is partitioned so that each of the 4 warp schedulers in an SMM controls 1 set of 32 FP32 CUDA cores, 1 set of 8 load/store units, and 1 set of 8 special function units. This is in contrast to Kepler, where each SMX has 4 schedulers that schedule to a shared pool of 6 sets of 32 FP32 CUDA cores, 2 sets of 16 load/store units, and 2 sets of 16 special function units.[12] These units are connected by a crossbar that uses power to allow the resources to be shared.[12] This crossbar is removed in Maxwell.[12] Texture units and FP64 CUDA cores are still shared.[11] SMM allows for a finer-grain allocation of resources than SMX, saving power when the workload isn't optimal for shared resources. Nvidia claims a 128 CUDA core SMM has 90% of the performance of a 192 CUDA core SMX.[11] Also, each Graphics Processing Cluster, or GPC, contains up to 4 SMX units in Kepler, and up to 5 SMM units in first generation Maxwell.[11]

GM107 supports CUDA Compute Capability 5.0 compared to 3.5 on GK110/GK208 GPUs and 3.0 on GK10x GPUs. Dynamic Parallelism and HyperQ, two features in GK110/GK208 GPUs, are also supported across the entire Maxwell product line.

Maxwell provides native shared memory atomic operations for 32-bit integers and native shared memory 32-bit and 64-bit compare-and-swap (CAS), which can be used to implement other atomic functions.

NVENC

Main article: Nvidia NVENC

Maxwell-based GPUs also contain the NVENC SIP block introduced with Kepler. Nvidia's video encoder, NVENC, is 1.5 to 2 times faster than on Kepler-based GPUs meaning it can encode video at 6 to 8 times playback speed.[11]

PureVideo

Main article: Nvidia PureVideo

Nvidia also claims an 8 to 10 times performance increase in PureVideo Feature Set E video decoding due to the video decoder cache paired with increases in memory efficiency. However, H.265 is not supported for full hardware decoding, relying on a mix of hardware and software decoding.[11] When decoding video, a new low power state "GC5" is used on Maxwell GPUs to conserve power.[11]

Second generation Maxwell (GM20x)

Second generation Maxwell introduced a several new technologies: Dynamic Super Resolution,[13] Third Generation Delta Color Compression,[14] Multi-Pixel Programming Sampling,[15] Nvidia VXGI (Real-Time-Voxel-Global Illumination),[16] VR Direct,[17][18][19] Multi-Projection Acceleration,[14] and Multi-Frame Sampled Anti-Aliasing(MFAA)[20] however support for Coverage-Sampling Anti-Aliasing(CSAA) was removed.[21] HDMI 2.0 support was also added.[22][23]

Second generation Maxwell also changed the ROP to memory controller ratio from 8:1 to 16:1.[24] However, some of the ROPs are generally idle in the GTX 970 because there are not enough enabled SMMs to give them work to do and therefore reduces its maximum fill rate.[25]

Second generation Maxwell also has up to 4 SMM units per GPC, compared to 5 SMM units per GPC.[24]

GM204 supports CUDA Compute Capability 5.2 compared to 5.0 on GM107/GM108 GPUs, 3.5 on GK110/GK208 GPUs and 3.0 on GK10x GPUs.[14][24][26]

Maxwell second generation GM20x GPUs have an upgraded NVENC which supports HEVC encoding and adds support for H.264 encoding resolutions at 1440p/60FPS & 4K/60FPS compared to NVENC on Maxwell first generation GM10x GPUs which only supported H.264 1080p/60FPS encoding.[19]

Maxwell GM206 GPU supports full fixed function HEVC decoding.[27]

GeForce 970 specifications controversy

Issues with the GeForce 970's performance were first brought up by users when they found out that the cards, while featuring 4 GB of memory, rarely accessed memory over the 3.5 GB boundary. Further testing and investigation eventually led to Nvidia issuing a statement that the card's initially announced specifications had been altered without notice before the card was made commercially available, and that the card took a performance hit once memory over the 3.5 GB limit were put into use.[28][29][30]

The card's back-end hardware specifications, initially announced as being identical to those of the GeForce 980, differed in the amount of L2 cache (1.75 MB versus 2 MB in the GeForce 980) and the amount of ROPs (56 versus 64 in the 980). Additionally, it was revealed that the card was designed to access its memory as a 3.5 GB section, plus a 0.5 GB one, access to the latter being 7 times slower than the first one.[31] The company then went on to promise a specific driver modification in order to alleviate the performance issues produced by the cutbacks suffered by the card.[32] However, Nvidia later clarified that the promise had been a miscommunication and there would be no specific driver update for GTX 970.[33] Nvidia claimed that it would assist customers who wanted refunds in obtaining them.[34]

Nvidia revealed that it is able to disable individual units, each containing 256KB of L2 cache and 8 ROPs, without disabling whole memory controllers.[35] This comes at the cost of dividing the memory bus into high speed and low speed segments that cannot be accessed at the same time unless one segment is reading while the other segment is writing because the L2/ROP unit managing both of the GDDR5 controllers shares the read return channel and the write data bus between the two GDDR5 controllers and itself.[35] This is used in the GeForce GTX 970, which therefore can be described as having 3.5 GB in its high speed segment on a 224-bit bus and 512 MB in a low speed segment on a 32-bit bus.[35]

Future

After Maxwell, the next architecture is code-named Pascal.[36] Nvidia has announced that the Pascal GPU will feature stacked DRAM, Unified Memory, and NVLink.[36]

Products

GeForce 900 (9xx) series

  • 1 Shader Processors : Texture mapping units : Render output units
  • 2 Pixel fillrate is calculated as the lowest of three numbers: number of ROPs multiplied by the base core clock speed, number of rasterizers multiplied by the number of fragments they can generate per rasterizer multiplied by the base core clock speed, and the number of streaming multiprocessors multiplied by the number of fragments per clock that they can output multiplied by the base clock rate.[25]
  • 3 Texture fillrate is calculated as the number of TMUs multiplied by the base core clock speed.
  • 4 Single precision performance is calculated as 2 times the number of shaders multiplied by the base core clock speed.
  • 5 Double precision performance of the GTX 980, GTX 970, and GTX 960 are 1/32 of single-precision performance.[37]
  • 6 SLI support connecting up to 4 identical GPUs card for a 4-way SLI configuration. Those support 4-way SLI can support 3-way & 2-way SLI, however a Dual-GPUs card is already 2-way SLI configuration internally therefore they support 4-way SLI with an identical Dual-GPUs card but do not support 3-way SLI.
  • 7 Due to the disabling of one or more L2 cache/ROP units without disabling all of the memory controllers attached to the disabled units, the memory has been segmented. One segment must be reading while the other must be writing to achieve the peak speed. Since the peak speed is impossible to reach with pure reads or pure writes, they and their associated buses are split in this table.
Model Launch Code name Fab (nm) Transistors (Million) Die size (mm2) GPU count Bus interface Memory (MiB)7 Core config1 Clock speeds Fillrate Memory API support (version) Processing Power (GFLOPS) GFLOPS/W Single Precision TDP (watts) SLI support6 Release Price (USD)
Base core clock (MHz) Boost core clock (MHz) Memory (MT/s) Pixel (GP/s)2 Texture (GT/s)3 Bandwidth (GB/s)7 Bus type Bus width (bit)7 DirectX OpenGL OpenCL Single precision4 Double precision5
GeForce GTX 960 [38] Jan 22, 2015 GM206 28 2940 227 1 PCIe 3.0 x16 2048
4096 		1024:64:32 1127 1178 7010 39.3 72.1 112 GDDR5 128 12.0[4][5] 4.5 1.2 2308 72.1 19.2 120 2-way $199
GeForce GTX 970 [39] Sep 18, 2014 GM204 28 5200 398 1 PCIe 3.0 x16 3584+512 [40] 1664:104:56 [41] 1050 1178 7010 54.6 109.2 192+28 [42] GDDR5 224+32 [35] 12.0[4][5] 4.5 1.2[43] 3494 109 24.1 145 3-way $329
GeForce GTX 980 [44] Sep 18, 2014 GM204 28 5200 398 1 PCIe 3.0 x16 4096 2048:128:64 1126 1216 7010 72.1 144 224 GDDR5 256 12.0[4][5] 4.5 1.2[1] 4612 144 28.0 165 4-way $549

GeForce 900M (9xxM) series

Some implementations may use different specifications.

Model Launch Code name Fab (nm) Transistors (Million) Die size (mm2) GPU count Bus interface Memory (MiB) Core config1 Clock speeds Fillrate Memory API support (version) Processing Power (GFLOPS) GFLOPS/W Single Precision TDP (watts) SLI support6
Base core clock (MHz) Boost core clock (MHz) Memory (MT/s) Pixel (GP/s)2 Texture (GT/s)3 Bandwidth (GB/s) Bus type Bus width (bit) DirectX OpenGL OpenCL Single precision4 Double precision5
GeForce GTX 965M [45][46] Jan 05, 2015 GM204 28 5200(?) 398(?) 1 PCIe 3.0 x16 2048 1024:64:32 944 ??? 5000 30.2 60.4 80 GDDR5 128 12.0[4][5] 4.5 1.2[1] 1933 60.41 Un­known Un­known Un­known
GeForce GTX 970M [47] Oct 07, 2014 GM204 28 5200 398 1 PCIe 3.0 x16 3072
6144 		1280:80:48 924 993 5012 37.0 73.9 120 GDDR5 192[48] 12.0[4][5] 4.5 1.2[1] 2365 73.9 Un­known Un­known Yes
GeForce GTX 980M [49] Oct 07, 2014 GM204 28 5200 398 1 PCIe 3.0 x16 4096
8192 		1536:96:64 1038 1127 5012 49.8 99.6 160 GDDR5 256[48] 12.0[4][5] 4.5 1.2[1] 3189 99.6 Un­known Un­known Yes

Chipset table

Main article: Comparison table of GeForce 900 Series

See also

References

  1. ^ a b c d e http://www.techpowerup.com/gpudb/2621/geforce-gtx-980.html
  2. ^ http://blogs.nvidia.com/blog/2014/09/19/maxwell-and-dx12-delivered/
  3. ^ http://blogs.msdn.com/b/directx/archive/2014/09/18/directx-12-lights-up-nvidia-s-maxwell-editor-s-day.aspx
  4. ^ a b c d e f g http://www.anandtech.com/show/8526/nvidia-geforce-gtx-980-review/4
  5. ^ a b c d e f g http://www.anandtech.com/show/8544/microsoft-details-direct3d-113-12-new-features
  6. ^ Nvidia Maxwell to be first GPU with ARM CPU in 2013, Guru3d.com
  7. ^ Nvidia Maxwell Graphics Processors to Have Integrated ARM General-Purpose Cores., xbitlabs.com
  8. ^ Nvidia: Next-Generation Maxwell Architecture Will Break New Grounds.., xbitlabs.com
  9. ^ http://www.anandtech.com/show/3939/gtc-2010-reporters-notebook-day-1-nvidia-announces-future-gpu-families-for-2011-and-2013
  10. ^ http://www.geforce.com/whats-new/articles/introducing-the-geforce-gtx-750-class
  11. ^ a b c d e f g Smith, Ryan; T S, Ganesh (18 February 2014). "The NVIDIA GeForce GTX 750 Ti and GTX 750 Review: Maxwell Makes Its Move". AnandTech. Archived from the original on 18 February 2014. Retrieved 18 February 2014.
  12. ^ a b c http://www.anandtech.com/show/7764/the-nvidia-geforce-gtx-750-ti-and-gtx-750-review-maxwell/3
  13. ^ http://www.geforce.com/whats-new/articles/dynamic-super-resolution-instantly-improves-your-games-with-4k-quality-graphics
  14. ^ a b c http://international.download.nvidia.com/geforce-com/international/pdfs/GeForce_GTX_980_Whitepaper_FINAL.PDF
  15. ^ http://www.geforce.com/hardware/technology/mfaa/technology
  16. ^ http://www.geforce.com/whats-new/articles/maxwells-voxel-global-illumination-technology-introduces-gamers-to-the-next-generation-of-graphics
  17. ^ http://www.geforce.com/whats-new/articles/maxwell-architecture-gpus-the-only-choice-for-virtual-reality-gaming
  18. ^ http://blogs.nvidia.com/blog/2014/09/18/maxwell-virtual-reality/
  19. ^ a b http://www.anandtech.com/show/8526/nvidia-geforce-gtx-980-review/5
  20. ^ http://www.geforce.com/whats-new/articles/multi-frame-sampled-anti-aliasing-delivers-better-performance-and-superior-image-quality
  21. ^ http://forums.realhardwarereviews.com/news/new-nvidia-maxwell-chips-do-not-support-fast-csaa/
  22. ^ http://www.geforce.com/whats-new/articles/maxwell-architecture-gtx-980-970
  23. ^ http://www.anandtech.com/show/8526/nvidia-geforce-gtx-980-review
  24. ^ a b c http://www.anandtech.com/show/8526/nvidia-geforce-gtx-980-review/3
  25. ^ a b http://techreport.com/blog/27143/here-another-reason-the-geforce-gtx-970-is-slower-than-the-gtx-980
  26. ^ http://devblogs.nvidia.com/parallelforall/maxwell-most-advanced-cuda-gpu-ever-made/
  27. ^ http://www.anandtech.com/show/8923/nvidia-launches-geforce-gtx-960
  28. ^ "NVIDIA Discloses Full Memory Structure and Limitations of GTX 970". PCPer.
  29. ^ "GeForce GTX 970 Memory Issue Fully Explained – Nvidia's Response". WCFTech.
  30. ^ "Why Nvidia's GTX 970 slows down when using more than 3.5GB VRAM". PCGamer.
  31. ^ "GeForce GTX 970: Correcting The Specs & Exploring Memory Allocation". AnandTech.
  32. ^ "NVIDIA Working on New Driver For GeForce GTX 970 To Tune Memory Allocation Problems and Improve Performance". WCFTech.
  33. ^ "NVIDIA clarifies no driver update for GTX 970 specifically". PC World.
  34. ^ http://www.pcper.com/news/Graphics-Cards/NVIDIA-Plans-Driver-Update-GTX-970-Memory-Issue-Help-Returns
  35. ^ a b c d http://www.anandtech.com/show/8935/geforce-gtx-970-correcting-the-specs-exploring-memory-allocation/2
  36. ^ a b http://blogs.nvidia.com/blog/2014/03/25/gpu-roadmap-pascal/
  37. ^ Smith, Ryan (September 18, 2014). "The NVIDIA GeForce GTX 980 Review: Maxwell Mark 2". AnandTech. p. 1. Retrieved September 19, 2014.
  38. ^ GeForce GTX 960 | Specifications | GeForce
  39. ^ GeForce GTX 970 | Specifications | GeForce
  40. ^ http://www.pcper.com/news/Graphics-Cards/NVIDIA-Responds-GTX-970-35GB-Memory-Issue
  41. ^ http://www.anandtech.com/show/8935/geforce-gtx-970-correcting-the-specs-exploring-memory-allocation
  42. ^ http://www.anandtech.com/show/8935/geforce-gtx-970-correcting-the-specs-exploring-memory-allocation/4
  43. ^ http://www.techpowerup.com/gpudb/2620/geforce-gtx-970.html
  44. ^ GeForce GTX 980 | Specifications | GeForce
  45. ^ GeForce GTX 965M | Specifications | GeForce
  46. ^ http://www.techpowerup.com/gpudb/2634/geforce-gtx-965m.html
  47. ^ GeForce GTX 970M | Specifications | GeForce
  48. ^ a b http://www.hardware.fr/focus/106/gtx-970-3-5-go-224-bit-lieu-4-go-256-bit.html
  49. ^ GeForce GTX 980M | Specifications | GeForce
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