GPU Wiki Architecture

TeraScale

Architecture notes pending source review.

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Architecture Overview

TeraScale is the VLIW5 (Very Long Instruction Word, 5-wide) shader architecture used across ATI and AMD discrete GPUs from 2007 through 2010, spanning the Radeon HD 2000, 3000, and 4000 series. It succeeded the R580/R600 design and represented ATI's first DirectX 10 GPU family. The RV770 die (Radeon HD 4870) was a landmark product: a 55nm design that delivered strong performance at a competitive price and forced NVIDIA to cut prices on its GeForce GTX 200 series.

Quick Facts

Architecture name
TeraScale (VLIW5)
Launch era / years active
2007 to 2010
Predecessor
R580 / Xenos (Xbox 360)
Successor
TeraScale 2
Process nodes
80nm (R600), 65nm (RV670), 55nm (RV770)
Important chips
R600 (HD 2900 XT), RV670 (HD 3870 / 3850), RV770 (HD 4870 / 4850), RV730 (HD 4670), RV710 (HD 4350)
Memory technologies
GDDR3 (early), GDDR4 (R600 / HD 2900 XT), GDDR5 (HD 4870)
CUDA / RT / Tensor generation
VLIW5 Stream Processors; DirectX 10 (R600/RV670), DirectX 10.1 (RV770 and later); OpenCL 1.0 (late models)
Consumer series
Radeon HD 2900 series, HD 3800 / 3600 / 3400 series, HD 4800 / 4600 / 4500 / 4300 series
Workstation / professional series
ATI FirePro V8700, V7750 (RV770-based)
Data center series
ATI FireStream 9250 (RV770-based compute card)
Source review status
Source review complete for primary consumer product line.

What this architecture changed

VLIW5 shader array: each shader processor cluster handles a 5-wide VLIW instruction bundle, requiring the compiler to pack instructions efficiently.
First ATI architecture with DirectX 10 compliance (R600), and first with DirectX 10.1 (RV770).
GDDR5 debut on a consumer GPU: HD 4870 was the first shipping consumer card with GDDR5 memory (256-bit at 115.2 GB/s).
HD 4870 X2: dual-GPU card on a single PCB, an early AMD dual-GPU reference design.
Stream computing (ATI Stream): early OpenCL-precursor compute support on select models.

Why it mattered

The TeraScale HD 4870 and HD 4850 are remembered as the GPUs that re-established ATI as a competitive force at the mainstream and high-end segments. The RV770 in particular forced aggressive NVIDIA price cuts and set a precedent for AMD using aggressive pricing and competitive architecture to pressure the market. The HD 4870's GDDR5 adoption was a key industry moment, making GDDR5 the dominant GPU memory standard for the following decade.

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Popular GPU entries

GPU Architecture Launch Date Shader Processors Memory Bus Width TDP/TBP Segment
Radeon HD 4850 TeraScale 2008-06-25 800 512 MB GDDR3 256-bit 110 W Gaming
Radeon HD 2900 PRO TeraScale 2007-12-12 320 512 MB GDDR3 256-bit 200 W Gaming
FirePro RG220A TeraScale 2010-05-04 80 512 MB GDDR3 256-bit 35 W Workstation
FirePro M7740 TeraScale 2009-08-04 640 1 GB GDDR5 128-bit 60 W Mobile
Radeon HD 2900 XT TeraScale 2007-05-14 320 512 MB GDDR3 512-bit 215 W Gaming
Mobility Radeon HD 4550 TeraScale 2010-01-01 80 512 MB GDDR3 64-bit Mobile
Radeon HD 4250 TeraScale 2009-02-25 40 512 MB DDR2 64-bit 25 W Gaming
Radeon HD 4870 Mac Edition TeraScale 2009-01-06 800 512 MB GDDR5 256-bit 150 W Gaming
Radeon HD 4350 AGP TeraScale 2008-09-30 80 512 MB DDR3 64-bit 20 W Gaming
All-In-Wonder HD 3650 TeraScale 2008-06-28 120 512 MB DDR2 128-bit 55 W Gaming