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{{Short description|Codename for a family of graphics processing unit microarchitectures}}{{Use mdy dates|date=November 2022}}{{More citations needed|date=March 2021}}TeraScale is the codename for a family of graphics processing unit microarchitectures developed by ATI Technologies/AMD and their second microarchitecture implementing the unified shader model following Xenos. TeraScale replaced the old fixed-pipeline microarchitectures and competed directly with Nvidia's first unified shader microarchitecture named Tesla.WEB,weblink The TeraScale 3 architecture of the HD 6990, Kevin Parrish, Tom's Hardware, March 9, 2011, April 8, 2015, WEB,weblink dead, Anatomy of AMD's TeraScale Graphics Engine,weblink" title="web.archive.org/web/20100613174446weblink">weblink June 13, 2010, November 21, 2021, TeraScale was used in Radeon HD 2000 manufactured in 80 nm and 65 nm, Radeon HD 3000 manufactured in 65 nm and 55 nm, Radeon HD 4000 manufactured in 55 nm and 40 nm, Radeon HD 5000 and Radeon HD 6000 manufactured in 40 nm. TeraScale was also used in the AMD Accelerated Processing Units code-named "Brazos", "Llano", "Trinity" and "Richland". TeraScale is even found in some of the succeeding graphics cards brands.TeraScale is a VLIW SIMD architecture, while Tesla is a RISC SIMD architecture, similar to TeraScale's successor Graphics Core Next.TeraScale implements HyperZ.WEB,weblink Feature matrix of the free and open-source "Radeon" graphics device driver, July 9, 2014, An LLVM code generator (i.e. a compiler back-end) is available for TeraScale,WEB,weblink [LLVMdev] RFC: R600, a new backend for AMD GPUs, Tom, Stellard, March 26, 2012, but it seems to be missing in LLVM's matrix.Target-specific Implementation Notes: Target Feature Matrix // The LLVM Target-Independent Code Generator, LLVM site. E.g. Mesa 3D makes use of it.

{{Anchor|first|1.0|1}}TeraScale 1 (VLIW)

factoids

| process = | entry =| midrange = | highend = | d3dversion = date=October 2019}}TeraScale (microarchitecture)#second>TeraScale 2| support status = Unsupported}}At SIGGRAPH 08 in December 2008, AMD employee Mike Houston described some of the TeraScale microarchitecture.WEB,weblink Anatomy of AMD's TeraScale microarchitecture, December 12, 2008, July 6, 2014, August 24, 2014,weblink" title="web.archive.org/web/20140824044552weblink">weblink dead, At FOSDEM09 Matthias Hopf from AMDs technology partner SUSE Linux presented a slide regarding the programming of open-source driver for the R600.WEB,weblink Archived copy, July 17, 2014, January 9, 2016,weblink" title="web.archive.org/web/20160109053346weblink">weblink dead,

Unified shaders

{{See also|Very long instruction word}}Previous GPU architectures implemented fixed-pipelines, i.e. there were distinct shader processors for each type of shader. TeraScale leverages many flexible shader processors which can be scheduled to process a variety of shader types, thereby significantly increasing GPU throughput (dependent on application instruction mix as noted below). The R600 core processes vertex, geometry, and pixel shaders as outlined by the Direct3D 10.0 specification for Shader Model 4.0 in addition to full OpenGL 3.0 support.AMD OpenGL 3.0 driver release on Jan 28, 2009The new unified shader functionality is based upon a very long instruction word (VLIW) architecture in which the core executes operations in parallel.Wasson, Scott. AMD Radeon HD 2900 XT graphics processor: R600 revealed, Tech Report, May 14, 2007A shader cluster is organized into 5 stream processing units. Each stream processing unit can retire a finished single precision floating point MAD (or ADD or MUL) instruction per clock, dot product (DP, and special cased by combining ALUs), and integer ADD.Beyond3D review: AMD R600 Architecture and GPU Analysis, retrieved June 2, 2007. The 5th unit is more complex and can additionally handle special transcendental functions such as sine and cosine. Each shader cluster can execute 6 instructions per clock cycle (peak), consisting of 5 shading instructions plus 1 branch.Notably, the VLIW architecture brings with it some classic challenges inherent to VLIW designs, namely that of maintaining optimal instruction flow. Additionally, the chip cannot co-issue instructions when one is dependent on the results of the other. Performance of the GPU is highly dependent on the mixture of instructions being used by the application and how well the real-time compiler in the driver can organize said instructions.R600 core includes 64 shader clusters, while RV610 and RV630 cores have 8 and 24 shader clusters respectively.

Hardware tessellation

TeraScale includes multiple units capable of carrying out tessellation. Those are similar to the programmable units of the Xenos GPU which is used in the Xbox 360.Tessellation was officially specified in the major API's starting with DirectX 11 and OpenGL 4. TeraScale 1 based GPU's (HD 2000, 3000 and 4000 series) are only conformant to Direct3D 10 and OpenGL 3.3 and implements therefore a different tessellation principle which uses vendor specific API extensions.NEWS,weblink AMD_vertex_shader_tessellator (OpenGL extension), Khronos Group, April 4, 2021, en, The TeraScale 2 based GPU's (starting with the Radeon HD 5000 series) were the first to conform with both Direct3D 11 and OpenGL 4.0 tesselation technique.NEWS,weblink Tessellation (OpenGL Wiki), Khronos Group, April 4, 2021, en, Although the TeraScale 1 tessellator is simpler in design, it is described by AMD as a subset of the later tesselation standard.NEWS,weblink Advanced Topics in GPU Tessellation: Algorithms and Lessons Learned, Natalya Tatarchuk, AMD, April 4, 2021, en, The TeraScale tessellator units allow the developers to take a simple polygon mesh and subdivide it using a curved surface evaluation function. There are different tessellation forms, such as Bézier surfaces with N-patches, B-splines and NURBS, and also some subdivision techniques of the surface, which usually includes displacement map some kind of a texture.WEB,weblink Radeon HD 2000 Series: 3D Architecture Explained | ExtremeTech, www.extremetech.com, Essentially, this allows a simple, low-polygon model to be increased dramatically in polygon density in real-time with very small impact on the performance. Scott Wasson of Tech Report noted during an AMD demo that the resulting model was so dense with millions of polygons that it appeared to be solid.The TeraScale tessellator is reminiscent of ATI TruForm, the brand name of an early hardware tessellation unit used initially in the Radeon 8500.WEB,weblink ATI TruForm – Powering the next generation Radeon, Witheiler, Matthew, AnandTech, May 29, 2001, January 30, 2016, ATI TruForm received little attention from software developers. A few games (such as Madden NFL 2004, Serious Sam, Unreal Tournament 2003 and 2004, and unofficially (The Elder Scrolls III: Morrowind|Morrowind)), had the support for the ATI's tesselation technology included. Such a slow adaptation has to do with the fact that it was not a feature shared with NVIDIA GPUs, since those had implemented a competing tessellation solution using Quintic-RT patches which had achieved even less support from the major game developers.WEB,weblink nVidia GeForce3 SDK WhitePaper, Since the Xbox 360's GPU is based on the ATI's architecture, Microsoft saw the hardware-accelerated surface tessellation as a major GPU feature. A couple of years later the tesselation feature became mandatory with the release of the DirectX 11 in 2009.While the tessellation principle introduced with TeraScale was not part of the OpenGL 3.3 or Direct3D 10.0 requirements, and competitors such as the GeForce 8 series lacked similar hardware, Microsoft has added the tessellation feature as part of their DirectX 10.1 future plans.The Future of DirectX {{webarchive|url=https://web.archive.org/web/20130616075611weblink |date=June 16, 2013 }} presentation, slide 24-29 Finally, Microsoft introduced tessellation as a required capability not with DirectX 10.1 but DirectX 11.NEWS,weblink Tessellation Stages (Windows Developer), Microsoft, April 4, 2021, en, GCN geometric processor is AMD's (which acquired the ATI's GPU business) most current solution for carrying out tessellation using the GPU.

Ultra-threaded dispatch processor

Although the R600 is a significant departure from previous designs, it still shares many features with its predecessor, the Radeon R520. The Ultra-Threaded Dispatch Processor is a major architectural component of the R600 core, just as it was with the Radeon X1000 GPUs. This processor manages a large number of in-flight threads of three distinct types (vertex, geometry, and pixel shaders) and switches amongst them as needed. With a large number of threads being managed simultaneously it is possible to reorganize thread order to optimally utilize the shaders. In other words, the dispatch processor evaluates what goes in the other parts of the R600 and attempts to keep processing efficiency as high as possible. There are lower levels of management as well; each SIMD array of 80 stream processors has its own sequencer and arbiter. The arbiter decides which thread to process next, while the sequencer attempts to reorder instructions for best possible performance within each thread.

Texturing and anti-aliasing

Texturing and final output aboard the R600 core is similar but also distinct from R580. R600 is equipped with 4 texture units that are decoupled (independent) from the shader core, like in the R520 and R580 GPUs.The render output units (ROPs) of Radeon HD 2000 series now performs the task of Multisample anti-aliasing (MSAA) with programmable sample grids and maximum of 8 sample points, instead of using pixel shaders as in the Radeon X1000 series. Also new is the capability to filter FP16 textures, popular with HDR lighting, at full-speed. ROP can also perform trilinear and anisotropic filtering on all texture formats. On R600, this totals 16 pixels per clock for FP16 textures, while higher precision FP32 textures filter at half-speed (8 pixels per clock).Anti-aliasing capabilities are more robust on R600 than on the R520 series. In addition to the ability to perform 8× MSAA, up from 6× MSAA on the R300 through R580, R600 has a new custom filter anti-aliasing (CFAA) mode. CFAA refers to an implementation of non-box filters that look at pixels around the particular pixel being processed in order to calculate the final color and anti-alias the image. CFAA is performed by shader, instead of in the ROPs. This brings greatly enhanced programmability because the filters can be customized, but may also bring potential performance issues because of the use of shader resources. As of launch of R600, CFAA utilizes wide and narrow tent filters. With these, samples from outside the pixel being processed are weighted linearly based upon their distance from the centroid of that pixel, with the linear function adjusted based on the wide or narrow filter chosen.

Memory controllers

Memory controllers are connected via internal bi-directional ring bus wrapped around the processor. In Radeon HD 2900, it is a 1,024-bit bi-directional ring bus (512-bit read and 512-bit write), with 8 64-bit memory channels for a total bus width of 512-bits on the 2900 XT.; in Radeon HD 3800, it is a 512-bit ring bus; in Radeon HD 2600 and HD 3600, it is a 256-bit ring bus; In Radeon HD 2400 and HD 3400, there is no ring bus.

Half-generation update

{{expand section|date=May 2009}}The series saw a half-generation update with die shrink (55 nm) variants: RV670, RV635 and RV620. All variants support PCI Express 2.0, DirectX 10.1 with Shader Model 4.1 features, dedicated ATI Unified Video Decoder (UVD) for all modelsWEB,weblink RV670 Cards & Specs Revealed, VR-Zone, August 22, 2007, and PowerPlay technology for desktop video cards.{{in lang|es}} MadboxPC coverage {{webarchive|url=https://web.archive.org/web/20121018143324weblink |date=October 18, 2012 }}, retrieved November 10, 2007Except the Radeon HD 3800 series, all variants supported 2 integrated DisplayPort outputs, supporting 24- and 30-bit displays for resolutions up to 2,560×1,600. Each output included 1, 2, or 4 lanes per output, with data rate up to 2.7 Gbit/s per lane.ATI claimed that the support of DirectX 10.1 can bring improved performance and processing efficiency with reduced rounding error (0.5 ULP compared with average error 1.0 ULP as tolerable error), better image details and quality, global illumination (a technique used in animated films, and more improvements to consumer gaming systems therefore giving more realistic gaming experience.ATI DirectX 10.1 whitepaper {{webarchive|url=https://web.archive.org/web/20100307081938weblink |date=March 7, 2010 }}, retrieved December 7, 2007 )

Video cards

• Radeon HD 2000 series
• Radeon HD 3000 series
• Radeon HD 4000 series

(see list of chips in those pages)

{{Anchor|TeraScale 2|second|2|2.0}}TeraScale 2 (VLIW5)

factoids

| process = | entry =| midrange = | highend = | d3dversion = TeraScale (microarchitecture)#first>TeraScale 1TeraScale (microarchitecture)#third>TeraScale 3| support status = Unsupported}}TeraScale 2 (VLIW5) was introduced with Radeon HD 5000 series GPUs in "Evergreen" generation.At HPG10 Mark Fowler presented the "Evergreen" and stated that e.g. 5870 (Cypress), 5770 (Juniper) and 5670 (Redwood) support max resolution of the 6 times 2560×1600 pixels, while the 5470 (Cedar) supports 4 times 2560×1600 pixels, important for AMD Eyefinity multi-monitor support.WEB,weblink Presenting Radeon HD 5000, With the release of Cypress, the Terascale graphics engine architecture has been upgraded with twice the number of stream cores, texture units and ROP units compared to the RV770. The architecture of stream cores is largely unchanged, but adds support for DirectX 11/DirectCompute 11 capabilities with new instructions.WEB,weblinkweblink" title="web.archive.org/web/20090927045522weblink">weblink dead, DirectX 11 in the Open: ATI Radeon HD 5870 Review, September 27, 2009, Also similar to RV770, four texture units are tied to 16 stream cores (each have five processing elements, making a total of 80 processing elements). This combination of is referred to as a SIMD core.Unlike the predecessor Radeon R700, as DirectX 11 mandates full developer control over interpolation, dedicated interpolators were removed, relying instead on the SIMD cores. The stream cores can handle the higher rounding precision fused multiply–add (FMA) instruction in both single and double precision which increases precision over multiply–add (MAD) and is compliant to IEEE 754-2008 standard.WEB,weblink GPU Archives, WePC | Let's build your dream gaming PC, The instruction sum of absolute differences (SAD) has been natively added to the processors. This instruction can be used to greatly improve the performance of some processes, such as video encoding and transcoding on the 3D engine. Each SIMD core is equipped with 32 KiB local data share and 8 kiB of L1 cache, while all SIMD cores share 64 KiB global data share.

Memory controller

Each memory controller ties to two quad ROPs, one per 64-bit channel, and dedicated 512 KiB L2 cache.

Power saving

AMD PowerPlay is supported, see there.

Chips

• Evergreen chips:
  • Cedar RV810
  • Cypress RV870
  • Hemlock R800
  • Juniper RV840
  • Redwood RV830
• Northern Islands chips:
  • Barts RV940
  • Caicos RV910
  • Turks RV930
• APU that include a TeraScale 2 IGP:
  • Llano
  • Ontario
  • Zacate

{{Anchor|TeraScale 3|third|3|3.0}}TeraScale 3 (VLIW4)

factoids

| process = | entry =| midrange = | highend = | d3dversion = TeraScale (microarchitecture)#second>TeraScale 2Graphics Core Next#first>Graphics Core Next 1| support status = Unsupported}}TeraScale 3 (VLIW4) replaces the previous 5-way VLIW designs with a 4-way VLIW design. The new design also incorporates an additional tessellation unit to improve Direct3D 11 performance.TeraScale 3 is introduced in the Radeon HD 6900-branded graphics cards and also implemented in the (AMD Accelerated Processing Unit#Piledriver architecture (2012): Trinity and Richland|Trinity and Richland) APUs.

Power saving

File:AMD PowerTune Bonaire.svg|thumb|Architecture of a newer version of PowerTune introduced with GCN1.1-chips]]AMD PowerTune, dynamic frequency scaling for GPUs, was introduced with the Radeon HD 6900 series on December 15, 2010 and has seen continued development, as documented in some reviews by AnandTech.WEB,weblink Redefining TDP With PowerTune, AnandTech, December 15, 2010, April 30, 2015, WEB,weblink Introducing PowerTune Technology With Boost, AnandTech, June 22, 2012, April 30, 2015, WEB,weblink The New PowerTune: Adding Further States, AnandTech, March 22, 2013, April 30, 2015, WEB,weblink PowerTune: Improved Flexibility & Fan Speed Throttling, AnandTech, October 23, 2014, April 30, 2015,

Chips

• Northern Islands chips:
  • Cayman RV970
  • Antilles R900
  • Trinity and Richland include a TeraScale 3 IGP

Successor

At HPG11 in August 2011 AMD employees Michael Mantor (Senior Fellow Architect) and Mike Houston (Fellow Architect) presented Graphics Core Next, the microarchitecture succeeding TeraScale.WEB,weblink AMD "Graphic Core Next": Low Power High Performance Graphics & Parallel Computer, August 5, 2011, July 6, 2014,

Comparison of TeraScale chips {| class"wikitable" style"font-size: 85%; text-align: center;"

! Microarchitecture! colspan="12" | TeraScale 1! colspan="7" | TeraScale 2! TeraScale 3! Chip1! R600! RV610! RV620! RV630! RV635! RV670! RV710! RV711! RV730! RV740! RV770! RV790! Cedar(RV810)! Redwood(RV830)! Juniper(RV840)! Cypress(RV870)! Caicos(RV910)! Turks(RV930)! Barts(RV940)! Cayman(RV970)! Code name| Pele| Laka| Koopa| Shaka| Wario| Boom Luigi| Mario| Walden| Wekiva| Spartan| ?| ?| ?| ?| ?| ?| Victoria| ?! Chip variant(s)| {{N/a}} M72M74 M82 M76 M86 M88 M92 M93 M96 M97 M98| {{N/a}} ParkRobson CapilanoMadisonPinewood BroadwayGranville HemlockLexington Seymour OnegaThamesWhistler Blackcomb Antilles! Fab (nm)| 80| 65| 55| 65 55| 40 55 40! Die size (mm2) 73 146 137 256 282 59 104 166 334 67 118 / 104 (Thames, Whistler) 255 / 212 (Blackcomb) 389! Transistors (million) 242 514 826 956 959 292 627 1,040 2,154 370 716 1,700 2,640! Transistor density(MTr/mm2) 3.3 3.5 6.0 3.7 3.4 4.9 6.0 6.3 6.4 5.5 6.1 / 6.9 (Thames, Whistler) 6.7 / 8.0 (Blackcomb) 6.8! Compute units 2 colspan="2" 1 4 8 colspan="2" | 24! Thread processors 4 colspan="2" 8 colspan="2" 40 8 20 40 80 / 20 (Lexington) 8 24 56 96! Stream processors 40 colspan="2" 80 320 640 colspan="2" | 1536! Texture mapping units 4 colspan="2" 8 colspan="2" 40 8 20 40 80 / 20 (Lexington) 8 24 56 96! Render output units 4 16 colspan="2" 16 4 8 16 32 / 8 (Lexington) 4 8 32 32! {{abbr|Z/Stencil OPS|Z/Stencil render output units}} 8 32 colspan="2" 64 4 colspan="3" | 128! L1 cache (KB) 32 per 4 SPs (Stream processors) colspan="6" 8 per CU! L2 cache (KB) 64 128 256 colspan="2" 128 colspan="2" 256 512 / 256 (Lexington) 128 256 colspan="2" | 512! Display Core Engine 2.0 3.0 2.0 3.0 2.0 colspan="4" 3.1 colspan="4" 5.0! Unified Video DecoderATI Avivo>Avivo HD colspan="5" 2.2 colspan="2" 2.3 colspan="4" | 3.1! Initial launch2007abbr=on}}2007abbr=on}}2008abbr=on}}2007abbr=on}}2008abbr=on}}2007abbr=on}}2008abbr=on}}2010abbr=on}}2008abbr=on}}2009abbr=on}}2008abbr=on}}2009abbr=on}}2010abbr=on}}2010abbr=on}}2009abbr=on}}2009abbr=on}} {{dtsFebruaryformat=my|abbr=on}}2010abbr=on}}2010abbr=on}}! Series R600 (Radeon HD 2000 series / Radeon HD 3000 series>Radeon HD 3000) R700 (Radeon HD 4000) Evergreen (Radeon HD 5000) Northern Islands (Radeon HD 6000)! ReferencesACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, VideoCardz, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 21, 2022 ACCESS-DATE=DECEMBER 21, 2022, VideoCardz, ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022, TechPowerUp, ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022 ACCESS-DATE=DECEMBER 22, 2022, TechPowerUp, 1 Duo chips such as R680 (2x RV670) and R700 (2x RV770) are not listed.WEB, ATI R680 GPU Specs,weblink December 21, 2022, TechPowerUp, WEB, ATI Radeon HD 3870 X2,weblink December 21, 2022, VideoCardz, WEB, ATI R700 GPU Specs,weblink December 21, 2022, TechPowerUp, WEB, ATI Radeon HD 4870 X2,weblink December 21, 2022, VideoCardz,

References

{{reflist|30em}}{{AMD graphics}}