A physics processing unit (PPU) is a dedicated

microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circ ...

designed to handle the calculations of

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which ...

, especially in the

physics engine A physics engine is computer software that provides an approximate simulation of certain physical systems, such as rigid body dynamics (including collision detection), soft body dynamics, and fluid dynamics, of use in the domains of computer gr ...

video game Video games, also known as computer games, are electronic games that involves interaction with a user interface or input device such as a joystick, controller, keyboard, or motion sensing device to generate visual feedback. This feedba ...

s. It is an example of

hardware acceleration Hardware acceleration is the use of computer hardware designed to perform specific functions more efficiently when compared to software running on a general-purpose central processing unit (CPU). Any transformation of data that can be calcula ...

. Examples of calculations involving a PPU might include

rigid body dynamics In the physical science of dynamics, rigid-body dynamics studies the movement of systems of interconnected bodies under the action of external forces. The assumption that the bodies are ''rigid'' (i.e. they do not deform under the action of ...

soft body dynamics Soft-body dynamics is a field of computer graphics that focuses on visually realistic physical simulations of the motion and properties of deformable objects (or ''soft bodies''). The applications are mostly in video games and films. Unlike in si ...

collision detection Collision detection is the computational problem of detecting the intersection of two or more objects. Collision detection is a classic issue of computational geometry and has applications in various computing fields, primarily in computer grap ...

fluid dynamics In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids— liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) a ...

, hair and clothing simulation,

finite element analysis The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, heat ...

, and fracturing of objects. The idea is having specialized processors offload time-consuming tasks from a computer's CPU, much like how a

GPU A graphics processing unit (GPU) is a specialized electronic circuit designed to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, mobi ...

performs graphics operations in the main CPU's place. The term was coined by

Ageia Ageia, founded in 2002, was a fabless semiconductor company. In 2004, Ageia acquired NovodeX, the company who created PhysX – a Physics Processing Unit chip capable of performing game physics calculations much faster than general purpose CPUs ...

to describe its PhysX chip. Several other technologies in the CPU-GPU spectrum have some features in common with it, although Ageia's product was the only complete one designed, marketed, supported, and placed within a system exclusively being a PPU.

History

An early academic PPU research project named SPARTA (Simulation of Physics on A Real-Time Architecture) was carried out at Penn State and University of Georgia. This was a simple

FPGA A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware d ...

based PPU that was limited to two dimensions. This project was extended into a considerably more advanced

ASIC An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficie ...

-based system named HELLAS. February 2006 saw the release of the first dedicated PPU PhysX from

(later merged into

nVidia Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to ...

). The unit is most effective in accelerating

particle systems A particle system is a technique in game physics, motion graphics, and computer graphics that uses many minute sprites, 3D models, or other graphic objects to simulate certain kinds of "fuzzy" phenomena, which are otherwise very hard to repro ...

, with only a small performance improvement measured for rigid body physics. The Ageia PPU is documented in depth in their US patent application #20050075849. Nvidia/Ageia no longer produces PPUs and hardware acceleration for physics processing, although it is now supported through some of their graphics processing units. File:SPARTA animation.jpg, alt=Example SPARTA animation, Example SPARTA animation File:SPARTA board.jpg, alt=SPARTA printed circuit board, SPARTA

Printed circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich str ...

File:Hellas die.jpg, alt=Hellas die photo, Hellas

die Die, as a verb, refers to death, the cessation of life. Die may also refer to: Games * Die, singular of dice, small throwable objects used for producing random numbers Manufacturing * Die (integrated circuit), a rectangular piece of a semicondu ...

photo

AGEIA PhysX

The first processor to be advertised being a PPU was named the PhysX chip, introduced by a

fabless semiconductor company Fabless manufacturing is the design and sale of hardware devices and semiconductor chips while outsourcing their fabrication (or ''fab'') to a specialized manufacturer called a semiconductor foundry. These foundries are typically, but not exclu ...

called

AGEIA Ageia, founded in 2002, was a fabless semiconductor company. In 2004, Ageia acquired NovodeX, the company who created PhysX – a Physics Processing Unit chip capable of performing game physics calculations much faster than general purpose CPUs ...

. Games wishing to take advantage of the PhysX PPU must use AGEIA's PhysX SDK, (formerly known as the NovodeX SDK). It consists of a general purpose RISC core controlling an array of custom

SIMD Single instruction, multiple data (SIMD) is a type of parallel processing in Flynn's taxonomy. SIMD can be internal (part of the hardware design) and it can be directly accessible through an instruction set architecture (ISA), but it shoul ...

floating point

VLIW Very long instruction word (VLIW) refers to instruction set architectures designed to exploit instruction level parallelism (ILP). Whereas conventional central processing units (CPU, processor) mostly allow programs to specify instructions to exe ...

processors working in local banked memories, with a switch-fabric to manage transfers between them. There is no cache-hierarchy like in a CPU or GPU. The PhysX was available from three companies akin to the way

video card A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer m ...

s are manufactured. ASUS,

BFG Technologies BFG Technologies was a privately held U.S.-based supplier of power supplies and video cards based on Nvidia graphics technology and a manufacturer of high-end gaming/home theater computer systems. BFG Technologies branded products were availabl ...

, and ELSA Technologies were the primary manufacturers. PCs with the cards already installed were available from system builders such as

Alienware Alienware is an American computer hardware subsidiary of Dell. Their product range is dedicated to gaming computers which can be identified by their alien-themed designs. Alienware was founded in 1996 by Nelson Gonzalez and Alex Aguila, and is ...

Dell Dell is an American based technology company. It develops, sells, repairs, and supports computers and related products and services. Dell is owned by its parent company, Dell Technologies. Dell sells personal computers (PCs), servers, data ...

, and

Falcon Northwest Falcon Northwest is a private company headquartered in Medford, Oregon. It designs, assembles, and markets high-end custom computers. The company was founded in 1992 and was one of the first to specialize in PCs built specifically for gaming. Hist ...

. In February 2008, after

Nvidia Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to ...

bought Ageia Technologies and eventually cut off the ability to process PhysX on the AGEIA PPU and NVIDIA GPUs in systems with active ATi/AMD GPUs, it seemed that PhysX went 100% to Nvidia. But in March 2008, Nvidia announced that it will make PhysX an open standard for everyone, so the main graphic-processor manufacturers will have PhysX support in the next generation graphics cards. Nvidia announced that PhysX will also be available for some of their released graphics cards just by downloading some new drivers. See

for a discussion of academic research PPU projects.

PhysX P1 (PPU) hardware specifications

ASUS and

bought licenses to manufacture alternate versions of AGEIA's PPU, the PhysX P1 with 128 MB GDDR3: * Multi-core device based on the

MIPS architecture MIPS (Microprocessor without Interlocked Pipelined Stages) is a family of reduced instruction set computer (RISC) instruction set architectures (ISA)Price, Charles (September 1995). ''MIPS IV Instruction Set'' (Revision 3.2), MIPS Technologies, ...

with integrated physics acceleration hardware and memory subsystem with "tons of cores" ** 125 million

transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...

sLegit Reviews - ASUS's AGEIA PhysX P1 Card
/ref> ** 182 mm²

size ** Fabrication process:

130 nm The 130 nanometer (130 nm) process refers to the level of semiconductor process technology that was reached in the 2000–2001 timeframe, by most leading semiconductor companies, like Intel, Texas Instruments, IBM, and TSMC. The origin of the ...

** Peak power consumption: 30 W * Memory: 128 MB GDDR3

RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...

with 128-bit interface * 32-bit PCI 3.0 (ASUS also made a

PCI Express PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common ...

version card) *

Sphere A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the c ...

collision tests: 530 million per second (maximum capability) *

Convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytop ...

collision tests: 530,000 per second (maximum capability) * Peak instruction bandwidth: 20 billion per second

Havok FX

The Havok SDK is a major competitor to the PhysX SDK, used in more than 150 games, including major titles like

Half-Life 2 ''Half-Life 2'' is a 2004 first-person shooter game developed by Valve Corporation, Valve. It was published by Valve through its distribution service Steam (service), Steam. Like the original ''Half-Life (video game), Half-Life'' (1998), ''Half- ...

Halo 3 ''Halo 3'' is a 2007 first-person shooter video game developed by Bungie for the Xbox 360 console. The third installment in the ''Halo'' franchise, the game concludes the story arc begun in 2001's '' Halo: Combat Evolved'' and continued in ...

and

Dead Rising is a series of action-adventure games created by Keiji Inafune. It was originally developed by Capcom until Capcom Vancouver took over developing the franchise. As of March 31, 2022, the game series has sold 15 million units worldwide and is ...

. To compete with the PhysX PPU, an edition known as Havok FX was to take advantage of multi-GPU technology from

ATI Ati or ATI may refer to: * Ati people, a Negrito ethnic group in the Philippines **Ati language (Philippines), the language spoken by this people group ** Ati-Atihan festival, an annual celebration held in the Philippines *Ati language (China), a ...

( AMD CrossFire) and

NVIDIA Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to ...

( SLI) using existing cards to accelerate certain physics calculations.Havok FX product information
Havok divides the physics simulation into ''effect'' and ''gameplay'' physics, with effect physics being offloaded (if possible) to the GPU as Shader Model 3.0 instructions and gameplay physics being processed on the CPU as normal. The important distinction between the two is that ''effect'' physics do not affect gameplay (dust or small debris from an explosion, for example); the vast majority of physics operations are still performed in software. This approach differs significantly from the PhysX SDK, which moves all calculations to the PhysX card if it is present. Since Havok's acquisition by

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 ser ...

, Havok FX appears to have been shelved or cancelled.

PPU vs. GPUs

The drive toward

GPGPU General-purpose computing on graphics processing units (GPGPU, or less often GPGP) is the use of a graphics processing unit (GPU), which typically handles computation only for computer graphics, to perform computation in applications traditiona ...

has made GPUs more suitable for the job of a PPU; DX10 added integer data types, unified shader architecture, and a geometry shader stage which allows a broader range of algorithms to be implemented; Modern GPUs support

compute shader In computing, a compute kernel is a routine compiled for high throughput accelerators (such as graphics processing units (GPUs), digital signal processors (DSPs) or field-programmable gate arrays (FPGAs)), separate from but used by a main prog ...

s, which run across an indexed space and don't require any graphical resources, just general purpose data buffers. NVidia

CUDA CUDA (or Compute Unified Device Architecture) is a parallel computing platform and application programming interface (API) that allows software to use certain types of graphics processing units (GPUs) for general purpose processing, an approach ...

provides a little more in the way of inter-thread communication and scratchpad-style workspace associated with the threads. Nonetheless GPUs are built around a larger number of longer latency, slower threads, and designed around texture and framebuffer data paths, and poor branching performance; this distinguishes them from PPUs and

Cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

as being less well optimized for taking over game world simulation tasks. The Codeplay Sieve compiler supports the PPU, indicating that the Ageia physX chip would be suitable for GPGPU type tasks. However Ageia seem unlikely to pursue this market.

PS2 – VU0

Although very different from the PhysX, one could argue the

PlayStation 2 The PlayStation 2 (PS2) is a home video game console developed and marketed by Sony Computer Entertainment. It was first released in Japan on 4 March 2000, in North America on 26 October 2000, in Europe on 24 November 2000, and in Australia on ...

's VU0 is an early, limited implementation of a PPU. Conversely, one could describe a PPU to a PS2 programmer as an evolved replacement for VU0. Its feature-set and placement within the system is geared toward accelerating game update tasks including physics and AI; it can offload such calculations working off its own instruction stream whilst the CPU is operating on something else. Being a DSP however, it is much more dependent on the CPU to do useful work in a game engine, and would not be capable of implementing a full physics API, so it cannot be classed as a PPU. Also VU0 is capable of providing additional vertex processing power, though this is more a property of the pathways in the system rather than the unit itself. This usage is similar to Havok FX or GPU physics in that an auxiliary unit's general purpose floating point power is used to complement the CPU in either graphics or physics roles.

History

AGEIA PhysX

PhysX P1 (PPU) hardware specifications

Havok FX

PPU vs. GPUs

PS2 – VU0

See also

References

External links