# Heterogeneous System Architecture

Heterogeneous System Architecture (HSA) is a cross-vendor set of specifications that allow for the integration of central processing units and graphics processors on the same bus, with shared memory and tasks. The HSA is being developed by the HSA Foundation, which includes (among many others) AMD and ARM. The platform's stated aim is to reduce communication latency between CPUs, GPUs and other compute devices, and make these various devices more compatible from a programmer's perspective,$^{:3}$ relieving the programmer of the task of planning the moving of data between devices' disjoint memories (as must currently be done with OpenCL or CUDA).
CUDA and OpenCL as well as most other fairly advanced programming languages can use HSA to increase their execution performance. Heterogeneous computing is widely used in system-on-chip devices such as tablets, smartphones, other mobile devices, and video game consoles. HSA allows programs to use the graphics processor for floating point calculations without separate memory or scheduling.

## Rationale

The rationale behind HSA is to ease the burden on programmers when offloading calculations to the GPU. Originally driven solely by AMD and called the FSA, the idea was extended to encompass processing units other than GPUs, such as other manufacturers' DSPs, as well.
* Steps performed when offloading calculations to the GPU on a non-HSA system
* Steps performed when offloading calculations to the GPU on a HSA system, using the HSA functionality
Modern GPUs are very well suited to perform single instruction, multiple data (SIMD) and single instruction, multiple threads (SIMT), while modern CPUs are still being optimized for branching. etc.

## Overview

Originally introduced by embedded systems such as the Cell Broadband Engine, sharing system memory directly between multiple system actors makes heterogeneous computing more mainstream. Heterogeneous computing itself refers to systems that contain multiple processing units – central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), or any type of application-specific integrated circuits (ASICs). The system architecture allows any accelerator, for instance a graphics processor, to operate at the same processing level as the system's CPU.
Among its main features, HSA defines a unified virtual address space for compute devices: where GPUs traditionally have their own memory, separate from the main (CPU) memory, HSA requires these devices to share page tables so that devices can exchange data by sharing pointers. This is to be supported by custom memory management units.$^{:6–7}$ To render interoperability possible and also to ease various aspects of programming, HSA is intended to be ISA-agnostic for both CPUs and accelerators, and to support high-level programming languages.
So far, the HSA specifications cover:

### HSA Intermediate Layer

HSAIL (Heterogeneous System Architecture Intermediate Language), a virtual instruction set for parallel programs
* similar to LLVM Intermediate Representation and SPIR (used by OpenCL and Vulkan)
* finalized to a specific instruction set by a JIT compiler
* make late decisions on which core(s) should run a task
* explicitly parallel
* supports exceptions, virtual functions and other high-level features
* debugging support

### HSA memory model

* compatible with C++11, OpenCL, Java and .NET memory models
* relaxed consistency
* designed to support both managed languages (e.g. Java) and unmanaged languages (e.g. C)
* will make it much easier to develop 3rd-party compilers for a wide range of heterogeneous products programmed in Fortran, C++, C++ AMP, Java, et al.

### HSA dispatcher and run-time

* designed to enable heterogeneous task queueing: a work queue per core, distribution of work into queues, load balancing by work stealing
* any core can schedule work for any other, including itself
* significant reduction of overhead of scheduling work for a core
Mobile devices are one of the HSA's application areas, in which it yields improved power efficiency.

### Block diagrams

The illustrations below compare CPU-GPU coordination under HSA versus under traditional architectures.
* Standard architecture with a discrete GPU attached to the PCI Express bus. Zero-copy between the GPU and CPU is not possible due to distinct physical memories.
* HSA brings unified virtual memory and facilitates passing pointers over PCI Express instead of copying the entire data.
* In partitioned main memory, one part of the system memory is exclusively allocated to the GPU. As a result, zero-copy operation is not possible.
* Unified main memory, where GPU and CPU are HSA-enabled. This makes zero-copy operation possible.
* The CPU's MMU and the GPU's IOMMU must both comply with HSA hardware specifications.

## Software support

Some of the HSA-specific features implemented in the hardware need to be supported by the operating system kernel and specific device drivers. For example, support for AMD Radeon and AMD FirePro graphics cards, and APUs based on Graphics Core Next (GCN), was merged into version 3.19 of the Linux kernel mainline, released on 8 February 2015. Programs do not interact directly with amdkfd, but queue their jobs utilizing the HSA runtime. This very first implementation, known as amdkfd, focuses on "Kaveri" or "Berlin" APUs and works alongside the existing Radeon kernel graphics driver.
Additionally, amdkfd supports heterogeneous queuing (HQ), which aims to simplify the distribution of computational jobs among multiple CPUs and GPUs from the programmer's perspective. Support for heterogeneous memory management (HMM), suited only for graphics hardware featuring version 2 of the AMD's IOMMU, was accepted into the Linux kernel mainline version 4.14.
Integrated support for HSA platforms has been announced for the "Sumatra" release of OpenJDK, due in 2015.
AMD APP SDK is AMD's proprietary software development kit targeting parallel computing, available for Microsoft Windows and Linux. Bolt is a C++ template library optimized for heterogeneous computing.
GPUOpen comprehends a couple of other software tools related to HSA. CodeXL version 2.0 includes an HSA profiler.

## Hardware support
### AMD

As of February 2015, only AMD's "Kaveri" A-series APUs (cf. "Kaveri" desktop processors and "Kaveri" mobile processors) and Sony's PlayStation 4 allowed the integrated GPU to access memory via version 2 of the AMD's IOMMU. Earlier APUs (Trinity and Richland) included the version 2 IOMMU functionality, but only for use by an external GPU connected via PCI Express.
Post-2015 Carrizo and Bristol Ridge APUs also include the version 2 IOMMU functionality for the integrated GPU.
The following table shows features of AMD's processors with 3D graphics, including APUs (see also: List of AMD processors with 3D graphics).
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* talk
| Platform | Platform | Platform | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | High, standard and low power | Low and ultra-low power | Low and ultra-low power | Low and ultra-low power | Low and ultra-low power | Low and ultra-low power | Low and ultra-low power | Low and ultra-low power | Low and ultra-low power | Low and ultra-low power |
| Codename | Server | Basic | | | | | | Toronto | | | | | | | | | | | | | | | | | |
| Codename | Server | Micro | | | | | | | | | | | | | | | | Kyoto | | | | | | | |
| Codename | Desktop | Performance | | | | | | | | | | | | | Raphael | Phoenix | | | | | | | | | |
| Codename | Desktop | Mainstream | Llano | Trinity | Richland | Kaveri | Kaveri Refresh (Godavari) | Carrizo | Bristol Ridge | Raven Ridge | Picasso | Renoir | Cezanne | | Raphael | Phoenix | | | | | | | | | |
| Codename | Desktop | Entry | Llano | Trinity | Richland | Kaveri | Kaveri Refresh (Godavari) | Carrizo | Bristol Ridge | Raven Ridge | Picasso | Renoir | Cezanne | | | | Phoenix | | | | | | | | | |
| Codename | Desktop | Basic | | | | | | | | | | | | | | | | Kabini | | | | Dalí | | | |
| Codename | Mobile | Performance | | | | | | | | | | Renoir | Cezanne | Rembrandt | Dragon Range | | | | | | | | | | |
| Codename | Mobile | Mainstream | Llano | Trinity | Richland | Kaveri | | Carrizo | Bristol Ridge | Raven Ridge | Picasso | Renoir Lucienne | Cezanne Barceló | Rembrandt | Dragon Range | Phoenix | | | | | | | | | |
| Codename | Mobile | Entry | Llano | Trinity | Richland | Kaveri | | Carrizo | Bristol Ridge | Raven Ridge | | | | | | | | | | | | Dalí | | | Mendocino |
| Codename | Mobile | Basic | | | | | | | | | | | | | | | Desna, Ontario, Zacate | Kabini, Temash | Beema, Mullins | Carrizo-L | Stoney Ridge | Dalí | Pollock | | Mendocino |
| Codename | Embedded | Embedded | | Trinity | | Bald Eagle | | Merlin Falcon, Brown Falcon | | Great Horned Owl | | Grey Hawk | | | | | Ontario, Zacate | Kabini | Steppe Eagle, Crowned Eagle, LX-Family | | Prairie Falcon | Banded Kestrel | | River Hawk | |
| Released | Released | Released | Aug 2011 | Oct 2012 | Jun 2013 | Jan 2014 | 2015 | Jun 2015 | Jun 2016 | Oct 2017 | Jan 2019 | Mar 2020 | Jan 2021 | Jan 2022 | Sep 2022 | Jan 2023 | Jan 2011 | May 2013 | Apr 2014 | May 2015 | Feb 2016 | Apr 2019 | Jul 2020 | Jun 2022 | Nov 2022 |
| CPU microarchitecture | CPU microarchitecture | CPU microarchitecture | K10 | Piledriver | Piledriver | Steamroller | Steamroller | Excavator | "Excavator+" | Zen | Zen+ | Zen 2 | Zen 3 | Zen 3+ | Zen 4 | Zen 4 | Bobcat | Jaguar | Puma | Puma+ | "Excavator+" | Zen | Zen | Zen+ | "Zen 2+" |
| ISA | ISA | ISA | x86-64 v1 | x86-64 v2 | x86-64 v2 | x86-64 v2 | x86-64 v2 | x86-64 v3 | x86-64 v3 | x86-64 v3 | x86-64 v3 | x86-64 v3 | x86-64 v3 | x86-64 v3 | x86-64 v4 | x86-64 v4 | x86-64 v1 | x86-64 v2 | x86-64 v2 | x86-64 v2 | x86-64 v3 | x86-64 v3 | x86-64 v3 | x86-64 v3 | x86-64 v3 |
| Socket | Desktop | Performance | — | — | — | — | — | — | — | — | — | — | — | — | AM5 | — | — | — | — | — | — | — | — | — | — |
| Socket | Desktop | Mainstream | — | — | — | — | — | AM4 | AM4 | AM4 | AM4 | AM4 | AM4 | — | AM5 | — | — | — | — | — | — | — | — | — | — |
| Socket | Desktop | Entry | FM1 | FM2 | FM2 | FM2+ | FM2+ | FM2+, AM4 | AM4 | AM4 | AM4 | AM4 | AM4 | — | — | — | | | — | — | — | — | — | — | — | — | — |
| Socket | Desktop | Basic | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | AM1 | — | — | — | FP5 | — | — | — |
| Socket | Other | Other | FS1 | FS1+, FP2 | FS1+, FP2 | FP3 | FP3 | FP4 | FP4 | FP5 | FP5 | FP6 | FP6 | FP7 | FL1 | FP7 FP7r2 FP8 | ? | FT1 | FT3 | FT3b | FT3b | FP4 | FP5 | FT5 | FP5 | FT6 |
| PCI Express version | PCI Express version | PCI Express version | 2.0 | 2.0 | 2.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 4.0 | 5.0 | 4.0 | 2.0 | 2.0 | 2.0 | 2.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| CXL | CXL | CXL | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Fab. (nm) | Fab. (nm) | Fab. (nm) | GF 32SHP (HKMG SOI) | GF 32SHP (HKMG SOI) | GF 32SHP (HKMG SOI) | GF 28SHP (HKMG bulk) | GF 28SHP (HKMG bulk) | GF 28SHP (HKMG bulk) | GF 28SHP (HKMG bulk) | GF 14LPP (FinFET bulk) | GF 12LP (FinFET bulk) | TSMC N7 (FinFET bulk) | TSMC N7 (FinFET bulk) | TSMC N6 (FinFET bulk) | CCD: TSMC N5 (FinFET bulk) cIOD: TSMC N6 (FinFET bulk) | TSMC 4nm (FinFET bulk) | TSMC N40 (bulk) | TSMC N28 (HKMG bulk) | GF 28SHP (HKMG bulk) | GF 28SHP (HKMG bulk) | GF 28SHP (HKMG bulk) | GF 14LPP (FinFET bulk) | GF 14LPP (FinFET bulk) | GF 12LP (FinFET bulk) | TSMC N6 (FinFET bulk) |
| Die area (mm$^2$) | Die area (mm$^2$) | Die area (mm$^2$) | 228 | 246 | 246 | 245 | 245 | 245 | 250 | 210 | 210 | 156 | 180 | 210 | CCD: (2x) 70 cIOD: 122 | 178 | 75 (+ 28 FCH) | 107 | 107 | ? | 125 | 149 | | | ~100 |
| Min TDP (W) | Min TDP (W) | Min TDP (W) | 35 | 17 | 17 | 17 | 17 | 12 | 12 | 12 | 12 | 10 | 10 | 15 | 65 | 35 | 4.5 | 4 | 3.95 | 10 | 6 | 6 | 6 | 12 | 8 |
| Max APU TDP (W) | Max APU TDP (W) | Max APU TDP (W) | 100 | 100 | 100 | 95 | 95 | 65 | 65 | 65 | 65 | 65 | 65 | 45 | 170 | 54 | 18 | 25 | 25 | 25 | 25 | 25 | 6 | 54 | 15 |
| Max stock APU base clock (GHz) | Max stock APU base clock (GHz) | Max stock APU base clock (GHz) | 3 | 3.8 | 4.1 | 4.1 | 4.1 | 3.7 | 3.8 | 3.6 | 3.7 | 3.8 | 4.0 | 3.3 | 4.7 | 4.3 | 1.75 | 2.2 | 2 | 2.2 | 3.2 | 2.6 | 1.2 | 3.35 | 2.8 |
| Max APUs per node | Max APUs per node | Max APUs per node | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Max core dies per CPU | Max core dies per CPU | Max core dies per CPU | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Max CCX per core die | Max CCX per core die | Max CCX per core die | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Max cores per CCX | Max cores per CCX | Max cores per CCX | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | 8 | 2 | 4 | 4 | 4 | 2 | 2 | 2 | 4 | 4 |
| Max CPU cores per APU | Max CPU cores per APU | Max CPU cores per APU | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | 16 | 8 | 2 | 4 | 4 | 4 | 2 | 2 | 2 | 4 | 4 |
| Max threads per CPU core | Max threads per CPU core | Max threads per CPU core | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 2 |
| Integer pipeline structure | Integer pipeline structure | Integer pipeline structure | 3+3 | 2+2 | 2+2 | 2+2 | 2+2 | 2+2 | 2+2 | 4+2 | 4+2 | 4+2+1 | 1+3+3+1+2 | 1+3+3+1+2 | 1+3+3+1+2 | 1+3+3+1+2 | 1+1+1+1 | 1+1+1+1 | 1+1+1+1 | 1+1+1+1 | 2+2 | 4+2 | 4+2 | 4+2 | 4+2+1 |
| i386, i486, i586, CMOV, NOPL, i686, PAE, NX bit, CMPXCHG16B, AMD-V, RVI, ABM, and 64-bit LAHF/SAHF | i386, i486, i586, CMOV, NOPL, i686, PAE, NX bit, CMPXCHG16B, AMD-V, RVI, ABM, and 64-bit LAHF/SAHF | i386, i486, i586, CMOV, NOPL, i686, PAE, NX bit, CMPXCHG16B, AMD-V, RVI, ABM, and 64-bit LAHF/SAHF | | | | | | | | | | | | | | | | | | | | | | | |
| IOMMU | IOMMU | IOMMU | — | v2 | v2 | v2 | v2 | v2 | v2 | v2 | v2 | v2 | v2 | v2 | v2 | v2 | v1 | v1 | v2 | v2 | v2 | v2 | v2 | v2 | v2 |
| BMI1, AES-NI, CLMUL, and F16C | BMI1, AES-NI, CLMUL, and F16C | BMI1, AES-NI, CLMUL, and F16C | — | | | | | | | | | | | | | | — | | | | | | | | | |
| MOVBE | MOVBE | MOVBE | — | — | — | — | — | | | | | | | | | | | | | | | | | | — | | | | | | | | | |
| AVIC, BMI2, RDRAND, and MWAITX/MONITORX | AVIC, BMI2, RDRAND, and MWAITX/MONITORX | AVIC, BMI2, RDRAND, and MWAITX/MONITORX | — | — | — | — | — | | | | | | | | | | — | — | — | — | | | | | |
| SME, TSME, ADX, SHA, RDSEED, SMAP, SMEP, XSAVEC, XSAVES, XRSTORS, CLFLUSHOPT, CLZERO, and PTE Coalescing | SME, TSME, ADX, SHA, RDSEED, SMAP, SMEP, XSAVEC, XSAVES, XRSTORS, CLFLUSHOPT, CLZERO, and PTE Coalescing | SME, TSME, ADX, SHA, RDSEED, SMAP, SMEP, XSAVEC, XSAVES, XRSTORS, CLFLUSHOPT, CLZERO, and PTE Coalescing | — | — | — | — | — | — | — | | | | | | | | — | — | — | — | — | | | | |
| GMET, WBNOINVD, CLWB, QOS, PQE-BW, RDPID, RDPRU, and MCOMMIT | GMET, WBNOINVD, CLWB, QOS, PQE-BW, RDPID, RDPRU, and MCOMMIT | GMET, WBNOINVD, CLWB, QOS, PQE-BW, RDPID, RDPRU, and MCOMMIT | — | — | — | — | — | — | — | — | — | | | | | | — | — | — | — | — | — | — | — | |
| MPK, VAES | MPK, VAES | MPK, VAES | — | — | — | — | — | — | — | — | — | — | | | | | — | — | — | — | — | — | — | — | — |
| SGX | SGX | SGX | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| FPUs per core | FPUs per core | FPUs per core | 1 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0.5 | 1 | 1 | 1 | 1 |
| Pipes per FPU | Pipes per FPU | Pipes per FPU | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
| FPU pipe width | FPU pipe width | FPU pipe width | 128-bit | 128-bit | 128-bit | 128-bit | 128-bit | 128-bit | 128-bit | 128-bit | 128-bit | 256-bit | 256-bit | 256-bit | 256-bit | 256-bit | 80-bit | 128-bit | 128-bit | 128-bit | 128-bit | 128-bit | 128-bit | 128-bit | 256-bit |
| CPU instruction set SIMD level | CPU instruction set SIMD level | CPU instruction set SIMD level | SSE4a | AVX | AVX | AVX | AVX | AVX2 | AVX2 | AVX2 | AVX2 | AVX2 | AVX2 | AVX2 | AVX-512 | AVX-512 | SSSE3 | AVX | AVX | AVX | AVX2 | AVX2 | AVX2 | AVX2 | AVX2 |
| 3DNow! | 3DNow! | 3DNow! | 3DNow!+ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| PREFETCH/PREFETCHW | PREFETCH/PREFETCHW | PREFETCH/PREFETCHW | | | | | | | | | | | | | | | | | | | | | | | |
| GFNI | GFNI | GFNI | — | — | — | — | — | — | — | — | — | — | — | — | | | — | — | — | — | — | — | — | — | — |
| AMX | AMX | AMX | — | — | — | — | — | — | — | — | — | — | — | — | — | — | | | | | | | | | | | | | | — | — | — | — | — | — | — | — | — |
| FMA4, LWP, TBM, and XOP | FMA4, LWP, TBM, and XOP | FMA4, LWP, TBM, and XOP | — | | | | | | | — | — | — | — | — | — | — | — | — | — | — | | — | — | — | — |
| FMA3 | FMA3 | FMA3 | — | | | | | | | | | | | | | | — | — | — | — | | | | | |
| AMD XDNA | AMD XDNA | AMD XDNA | — | — | — | — | — | — | — | — | — | — | — | — | — | | — | — | — | — | — | — | — | — | — |
| L1 data cache per core (KiB) | L1 data cache per core (KiB) | L1 data cache per core (KiB) | 64 | 16 | 16 | 16 | 16 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 |
| L1 data cache associativity (ways) | L1 data cache associativity (ways) | L1 data cache associativity (ways) | 2 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 |
| L1 instruction caches per core | L1 instruction caches per core | L1 instruction caches per core | 1 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0.5 | 1 | 1 | 1 | 1 |
| Max APU total L1 instruction cache (KiB) | Max APU total L1 instruction cache (KiB) | Max APU total L1 instruction cache (KiB) | 256 | 128 | 128 | 192 | 192 | 192 | 192 | 256 | 256 | 256 | 256 | 256 | 512 | 256 | 64 | 64 | 128 | 128 | 96 | 128 | 128 | 128 | 128 |
| L1 instruction cache associativity (ways) | L1 instruction cache associativity (ways) | L1 instruction cache associativity (ways) | 2 | 2 | 2 | 3 | 3 | 3 | 3 | 4 | 4 | 8 | 8 | 8 | 8 | 8 | 2 | 2 | 2 | 2 | 3 | 4 | 4 | 4 | 8 |
| L2 caches per core | L2 caches per core | L2 caches per core | 1 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0.5 | 1 | 1 | 1 | 1 |
| Max APU total L2 cache (MiB) | Max APU total L2 cache (MiB) | Max APU total L2 cache (MiB) | 4 | 4 | 4 | 4 | 4 | 2 | 2 | 2 | 2 | 4 | 4 | 4 | 16 | | 1 | 2 | 2 | 2 | 1 | 1 | 1 | 2 | 2 |
| L2 cache associativity (ways) | L2 cache associativity (ways) | L2 cache associativity (ways) | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 16 | 16 | 16 | 16 | 16 | 8 | 8 | 8 | 8 |
| Max on--die L3 cache per CCX (MiB) | Max on--die L3 cache per CCX (MiB) | Max on--die L3 cache per CCX (MiB) | — | — | — | — | — | — | — | 4 | 4 | 4 | 16 | 16 | 32 | | — | — | — | — | — | — | 4 | 4 | 4 | 4 |
| Max 3D V-Cache per CCD (MiB) | Max 3D V-Cache per CCD (MiB) | Max 3D V-Cache per CCD (MiB) | — | — | — | — | — | — | — | — | — | — | — | — | 64 | — | — | — | — | — | — | — | — | — | — | — |
| Max total in-CCD L3 cache per APU (MiB) | Max total in-CCD L3 cache per APU (MiB) | Max total in-CCD L3 cache per APU (MiB) | — | — | — | — | — | — | — | 4 | 4 | 8 | 16 | 16 | 64 | | — | — | — | — | — | — | 4 | 4 | 4 | 4 |
| Max. total 3D V-Cache per APU (MiB) | Max. total 3D V-Cache per APU (MiB) | Max. total 3D V-Cache per APU (MiB) | — | — | — | — | — | — | — | — | — | — | — | — | 64 | — | — | — | — | — | — | — | — | — | — | — |
| Max. board L3 cache per APU (MiB) | Max. board L3 cache per APU (MiB) | Max. board L3 cache per APU (MiB) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Max total L3 cache per APU (MiB) | Max total L3 cache per APU (MiB) | Max total L3 cache per APU (MiB) | — | — | — | — | — | — | — | 4 | 4 | 8 | 16 | 16 | 128 | | — | — | — | — | — | — | 4 | 4 | 4 | 4 |
| APU L3 cache associativity (ways) | APU L3 cache associativity (ways) | APU L3 cache associativity (ways) | — | — | — | — | — | — | — | 16 | 16 | 16 | 16 | 16 | 16 | 16 | — | — | — | — | — | — | 16 | 16 | 16 | 16 |
| L3 cache scheme | L3 cache scheme | L3 cache scheme | — | — | — | — | — | — | — | Victim | Victim | Victim | Victim | Victim | Victim | Victim | — | — | — | — | — | — | Victim | Victim | Victim | Victim |
| Max. L4 cache | Max. L4 cache | Max. L4 cache | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Max stock DRAM support | Max stock DRAM support | Max stock DRAM support | DDR3-1866 | DDR3-1866 | DDR3-2133 | DDR3-2133 | DDR3-2133 | DDR3-2133, DDR4-2400 | DDR4-2400 | DDR4-2933 | DDR4-2933 | DDR4-3200, LPDDR4-4266 | DDR4-3200, LPDDR4-4266 | DDR5-4800, LPDDR5-6400 | DDR5-5200 | DDR5-5600, LPDDR5x-7500 | DDR3L-1333 | DDR3L-1600 | DDR3L-1866 | DDR3L-1866 | DDR3-1866, DDR4-2400 | DDR4-2400 | DDR4-1600 | DDR4-3200 | LPDDR5-5500 |
| Max DRAM channels per APU | Max DRAM channels per APU | Max DRAM channels per APU | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 2 | 2 |
| Max stock DRAM bandwidth (GB/s) per APU | Max stock DRAM bandwidth (GB/s) per APU | Max stock DRAM bandwidth (GB/s) per APU | 29.866 | 29.866 | 34.132 | 34.132 | 34.132 | 38.400 | 38.400 | 46.932 | 46.932 | 68.256 | 68.256 | 102.400 | 83.200 | 120.000 | 10.666 | 12.800 | 14.933 | 14.933 | 19.200 | 38.400 | 12.800 | 51.200 | 88.000 |
| GPU microarchitecture | GPU microarchitecture | GPU microarchitecture | TeraScale 2 (VLIW5) | TeraScale 3 (VLIW4) | TeraScale 3 (VLIW4) | GCN 2nd gen | GCN 2nd gen | GCN 3rd gen | GCN 3rd gen | GCN 5th gen | GCN 5th gen | GCN 5th gen | GCN 5th gen | RDNA 2 | RDNA 2 | RDNA 3 | TeraScale 2 (VLIW5) | GCN 2nd gen | GCN 2nd gen | GCN 2nd gen | GCN 3rd gen | GCN 5th gen | GCN 5th gen | GCN 5th gen | RDNA 2 |
| GPU instruction set | GPU instruction set | GPU instruction set | TeraScale instruction set | TeraScale instruction set | TeraScale instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | RDNA instruction set | RDNA instruction set | RDNA instruction set | TeraScale instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | GCN instruction set | RDNA instruction set |
| Max stock GPU base clock (MHz) | Max stock GPU base clock (MHz) | Max stock GPU base clock (MHz) | 600 | 800 | 844 | 866 | 866 | 1108 | 1108 | 1250 | 1400 | 2100 | 2100 | 2400 | 400 | | 538 | 600 | ? | 847 | 900 | 1200 | 600 | 1300 | 1900 |
| Max stock GPU base GFLOPS | Max stock GPU base GFLOPS | Max stock GPU base GFLOPS | 480 | 614.4 | 648.1 | 886.7 | 886.7 | 1134.5 | 1134.5 | 1760 | 1971.2 | 2150.4 | 2150.4 | 3686.4 | 102.4 | | 86 | ? | ? | ? | 345.6 | 460.8 | 230.4 | 1331.2 | 486.4 |
| 3D engine | 3D engine | 3D engine | Up to 400:20:8 | Up to 384:24:6 | Up to 384:24:6 | Up to 512:32:8 | Up to 512:32:8 | Up to 512:32:8 | Up to 512:32:8 | Up to 704:44:16 | Up to 704:44:16 | Up to 512:32:8 | Up to 512:32:8 | 768:48:8 | 128:8:4 | | 80:8:4 | 128:8:4 | 128:8:4 | 128:8:4 | Up to 192:12:8 | Up to 192:12:4 | 192:12:4 | Up to 512:?:? | 128:?:? |
| 3D engine | 3D engine | 3D engine | IOMMUv1 | IOMMUv1 | IOMMUv1 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv1 | IOMMUv1 | ? | ? | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 | IOMMUv2 |
| Video decoder | Video decoder | Video decoder | UVD 3.0 | UVD 3.0 | UVD 3.0 | UVD 4.2 | UVD 4.2 | UVD 6.0 | UVD 6.0 | VCN 1.0 | VCN 1.0 | VCN 2.1 | VCN 2.2 | VCN 3.1 | VCN 3.1 | ? | UVD 3.0 | UVD 4.0 | UVD 4.2 | UVD 4.2 | UVD 6.2 | VCN 1.0 | VCN 1.0 | VCN 1.0 | VCN 3.1 |
| Video encoder | Video encoder | Video encoder | — | VCE 1.0 | VCE 1.0 | VCE 2.0 | VCE 2.0 | VCE 3.1 | VCE 3.1 | VCN 1.0 | VCN 1.0 | VCN 2.1 | VCN 2.2 | VCN 3.1 | VCN 3.1 | ? | — | VCE 2.0 | VCE 2.0 | VCE 2.0 | VCE 3.4 | VCN 1.0 | VCN 1.0 | VCN 1.0 | VCN 3.1 |
| AMD Fluid Motion | AMD Fluid Motion | AMD Fluid Motion | | | | | | | | | | | | | | | | | | | | | | | |
| GPU power saving | GPU power saving | GPU power saving | PowerPlay | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerPlay | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune | PowerTune |
| TrueAudio | TrueAudio | TrueAudio | — | — | — | | | | | | | | ? | ? | ? | ? | — | | | | | | | | |
| FreeSync | FreeSync | FreeSync | — | — | — | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | — | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 | 1 2 |
| HDCP | HDCP | HDCP | ? | ? | ? | 1.4 | 1.4 | 1.4 | 1.4 | 2.2 | 2.2 | 2.2 | 2.2 | 2.3 | 2.3 | 2.3 | ? | 1.4 | 1.4 | 1.4 | 1.4 | 2.2 | 2.2 | 2.2 | 2.3 |
| PlayReady | PlayReady | PlayReady | — | — | — | — | — | — | — | 3.0 not yet | 3.0 not yet | 3.0 not yet | 3.0 not yet | 3.0 not yet | 3.0 not yet | 3.0 not yet | — | — | — | — | — | 3.0 not yet | 3.0 not yet | 3.0 not yet | 3.0 not yet |
| Supported displays | Supported displays | Supported displays | 2–3 | 2–4 | 2–4 | 2–4 | 2–4 | 3 | 3 | 3 (desktop) 4 (mobile, embedded) | 3 (desktop) 4 (mobile, embedded) | 4 | 4 | 4 | 4 | 4 | 2 | 2 | 2 | 2 | 3 | 4 | | 4 | 4 |
| /drm/radeon | /drm/radeon | /drm/radeon | | | | | | | — | — | — | — | — | — | — | — | | | | | — | — | — | — | — |
| /drm/amdgpu | /drm/amdgpu | /drm/amdgpu | — | — | — | | | | | | | | | | | | — | | | | | | | | |
* ↑ For FM2+ Excavator models: A8-7680, A6-7480 & Athlon X4 845.
* ↑ A PC would be one node.
* ↑ An APU combines a CPU and a GPU. Both have cores.
* ↑ Requires firmware support.
* 1 2 Requires firmware support.
* ↑ No SSE4. No SSSE3.
* ↑ Single-precision performance is calculated from the base (or boost) core clock speed based on a FMA operation.
* ↑ Unified shaders : texture mapping units : render output units
* 1 2 To play protected video content, it also requires card, operating system, driver, and application support. A compatible HDCP display is also needed for this. HDCP is mandatory for the output of certain audio formats, placing additional constraints on the multimedia setup.
* ↑ To feed more than two displays, the additional panels must have native DisplayPort support. Alternatively active DisplayPort-to-DVI/HDMI/VGA adapters can be employed.
* 1 2 DRM (Direct Rendering Manager) is a component of the Linux kernel. Support in this table refers to the most current version.

### ARM

ARM's Bifrost microarchitecture, as implemented in the Mali-G71, is fully compliant with the HSA 1.1 hardware specifications. As of June 2016, ARM has not announced software support that would use this hardware feature.