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 firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the b ...

of a

graphics 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 moni ...

in a (usually

IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible de facto standard. Released on August 12, 1981, it was created by a team ...

-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 i ...

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 BIO ...

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

UEFI UEFI (Unified Extensible Firmware Interface) is a set of specifications written by the UEFI Forum. They define the architecture of the platform firmware used for booting and its interface for interaction with the operating system. Examples of f ...

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

UEFI GOP UEFI (Unified Extensible Firmware Interface) is a set of specifications written by the UEFI Forum. They define the architecture of the platform firmware used for booting and its interface for interaction with the operating system. Examples of f ...

. 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 vendor-specific settings such as card name, clock frequencies, VRAM types & voltages. The video BIOS interfaces software to the video

chipset In a computer system, a chipset is a set of electronic components in one or more integrated circuits known as a "Data Flow Management System" that manages the data flow between the processor, memory and peripherals. It is usually found on the mo ...

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 clearly ...

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, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

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 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 ...

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

video memory Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxide ...

Modding

Up until mid 2010s video ROMs were user-editable/modifiable which allowed to configure GPU features like core and VRAM clocks, or adjust fan speed curves and in certain cases a different GPU class could have been unlocked. 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 An original equipment manufacturer (OEM) is generally perceived as a company that produces non-aftermarket parts and equipment that may be marketed by another manufacturer. It is a common industry term recognized and used by many professional or ...

, thus unlocking higher performance modes or changing its mode of operation. Older NVIDIA GPUs 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, named after James Clerk Maxwell. They are produce ...

could be edited using NiBiTor (NVIDIA BIOS Editor).

References

Graphics cards BIOS {{Compu-graphics-stub

Modding

See also

References