Video BIOS is the

BIOS In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is a type of firmware used to provide runtime services for operating systems and programs and to perform hardware initialization d ...

of a

graphics card A graphics card (also called a video card, display card, graphics accelerator, graphics adapter, VGA card/VGA, video adapter, display adapter, or colloquially GPU) is a computer expansion card that generates a feed of graphics output to a displa ...

in a (usually

IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the List of IBM Personal Computer models, IBM PC model line and the basis for the IBM PC compatible ''de facto'' standard. Released on ...

-derived) computer. It initializes the

at the computer's boot time. It also implements

INT 10h INT 10h, INT 10H or INT 16 is shorthand for BIOS interrupt call 10 hex, the 17th interrupt vector in an x86-based computer system. The BIOS typically sets up a real mode interrupt handler at this vector that provides video services. Such services ...

interrupt and

VESA BIOS Extensions VESA BIOS Extensions (VBE) is a VESA standard, currently at version 3, that defines the interface that can be used by software to access compliant video boards at high resolutions and bit depths. This is opposed to the "traditional" INT 10h B ...

(VBE) for basic text and videomode output before a specific video driver is loaded. In

UEFI Unified Extensible Firmware Interface (UEFI, as an acronym) is a Specification (technical standard), specification for the firmware Software architecture, architecture of a computing platform. When a computer booting, is powered on, the UEFI ...

2.x systems, the INT 10h and the VBE are replaced by the

UEFI GOP Unified Extensible Firmware Interface (UEFI, as an acronym) is a specification for the firmware architecture of a computing platform. When a computer is powered on, the UEFI implementation is typically the first that runs, before starting th ...

. Much the way the system BIOS provides a set of functions that are used by software programs to access the system hardware, the video BIOS provides a set of video-related functions that are used by programs to access the video hardware, as well as storing video card settings such as card name, clock frequencies, VRAM types & voltages, and oncard VRM powers. The video BIOS interfaces software to the video

chipset In a computer system, a chipset is a set of electronic components on one or more integrated circuits that manages the data flow between the processor, memory and peripherals. The chipset is usually found on the motherboard of computers. Chips ...

in the same way that the system BIOS does for the system chipset. The ROM also contained a basic font set to upload to the video adapter font RAM, if the video card did not contain a font ROM with this font set instead. Unlike some other hardware components, the video card usually needs to be active very early during the

boot A boot is a type of footwear. Most boots mainly cover the foot and the ankle, while some also cover some part of the lower calf. Some boots extend up the leg, sometimes as far as the knee or even the hip. Most boots have a heel that is clearl ...

process so that the user can see what is going on. This requires the card to be activated before any

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

begins loading; thus it needs to be activated by the

, the only software that is present at this early stage. The system BIOS loads the video BIOS from the card's ROM into system RAM and transfers control to it early in the boot sequence. Early PCs contained functions for driving MDA and CGA cards in the system BIOS, and those cards did not have any Video BIOS built in. When the EGA card was first sold in 1984, the Video BIOS was introduced to make these cards compatible with existing PCs whose BIOS did not know how to drive an EGA card. Ever since, EGA/VGA and all enhanced VGA compatible cards have included a Video BIOS. When the computer is started, some graphics cards (usually certain

Nvidia Nvidia Corporation ( ) is an American multinational corporation and technology company headquartered in Santa Clara, California, and incorporated in Delaware. Founded in 1993 by Jensen Huang (president and CEO), Chris Malachowsky, and Curti ...

cards) display their vendor, model, Video BIOS version and amount of

video memory Video random-access memory (VRAM) is dedicated computer memory used to store the pixels and other graphics data as a framebuffer to be rendered on a computer monitor. It often uses a different technology than other computer memory, in order to b ...

Modding

Up until the mid 2010s, video ROMs were user-editable/modifiable, which allowed users to configure GPU features like core clocks, VRAM clocks or fan speed curves. In certain cases, a different GPU class could have been unlocked (the most famous example being the

AMD Radeon Radeon () is a brand of computer products, including graphics processing units, random-access memory, RAM disk software, and solid-state drives, produced by Radeon Technologies Group, a division of AMD. The brand was launched in 2000 by ATI ...

HD6950 and HD6970 series who shared the same GPU, with some

shading Shading refers to the depiction of depth perception in 3D models (within the field of 3D computer graphics) or illustrations (in visual art) by varying the level of darkness. Shading tries to approximate local behavior of light on the object's ...

units disabled through the BIOS on the former. These units could be unlocked by replacing the original HD6950 BIOS with an HD6970 BIOS. The card would then behave as an actual HD6970). However, nowadays both NVIDIA and AMD digitally sign video firmware, which has made it impossible to make any changes to it. Still, in many cases, users can flash a firmware image from another OEM, thus unlocking higher performance modes or changing its mode of operation. Older NVIDIA GPU ROMs up until the

GeForce 900 series The GeForce 900 series is a family of graphics processing units developed by Nvidia, succeeding the GeForce 700 series and serving as the high-end introduction to the Maxwell (microarchitecture), Maxwell microarchitecture, named after James Cle ...

could be edited using NiBiTor (NVIDIA BIOS Editor).

References

Graphics cards BIOS {{Compu-graphics-stub

Modding

See also

References