Video card

Video card

Graphics card (more famous as a graphics card, video) - a device that converts a graphic image that is stored as the contents of a computer memory or the adapter itself, in some form, intended for the upcoming display monitor. In real time, this feature is essential and lost in the first place, under the graphics adapter device understand the GPU - graphics accelerator, which is developing the graphical form.

VideokartaTraditsionno graphics card is an expansion board and inserted into the expansion slot, universal (PCI-Express, PCI, ISA, VLB, EISA, MCA) or special (AGP), but there is also integrated (built-in) on the system board (as in the form of a separate chip and as part of the Northbridge or CPU).

Innovative graphics are not limited to a simple conclusion of the image, they have built-in graphics processor, which can create additional processing, removing this puzzle from the CPU computer.

1. GPU (Graphics processing unit - a graphic processor device) - is engaged in the calculations displayed image, relieving the CPU of this duty, makes payments to process commands three-dimensional graphics. Considered the foundation of the graphics card specifically depend on it performance and capabilities of the device. Innovative graphics processing complexity is not much inferior to the central processing computer, and often surpass it as the number of transistors, and in processing power, thanks to the great number of universal computational units. However, the structure of the previous generation GPU traditionally implies the presence of multiple processing units of disk imaging, namely: a processing unit 2D-graphics processing unit 3D-graphics, in turn, is usually divided into geometric kernel (plus cash vertices) and ROP units (plus the texture cache ), etc.

2. video controller - is responsible for creating the image in memory, RAMDAC gives commands to create the sweep signal to the monitor and perform query processing CPU. In addition, traditionally in the external data bus controller (for example, PCI or AGP), the controller internal data bus and the memory controller. The width of the internal bus and memory bus are traditionally higher than the outside (64, 128 or 256 bits suprotiv 16 or 32) and many more video controllers built and RAMDAC. Innovative graphics cards (ATI, nVidia) traditionally have at least 2-video controllers, working independently of each other, and control immediately by one or more monitors each.

3. video memory - serves as a frame buffer, which is saved in the image generated and continuously variable graphics processor and displayed on the monitor screen (or multiple displays). In memory saved up as intermediate components visible on the screen images and other data. Video memory is of several types, which differ in the speed of access and frequency. Innovative graphics memory kit form DDR, DDR2, GDDR3, GDDR4 and GDDR5. Should also be borne in mind that in addition to memory, located on the graphics card, advanced graphics processors typically use in the work part of the computer system memory, direct access to the video driver being organized via the AGP or PCIE. In the case of architecture UMA video memory is used as part of a computer system memory.

4. digital-to-analog converter (DAC, RAMDAC - Random Access Memory Digital-to-Analog Converter) - provides for the transformation of the image formed by the video controller, the color intensity values to the analog monitor. The possible range of color images is determined only by the parameters RAMDAC. Most often RAMDAC has four main sections - 3-analog converter, and 1 for each color channel (red, green, blue, RGB), and SRAM to store data on the gamma correction. Most bit DACs have 8 bits per channel - comes with 256 levels of brightness for each primary color, for a total of 16.7 million colors (and by gamma correction is likely to display the original 16.7 million colors in a much larger color space) . Some have a bit RAMDAC per channel 10 bit (1024 values of brightness), which allows you to immediately display more than 1 billion colors, but this possibility is almost never used. To support different monitor often set the second DAC. It is worth to notice that the screens and projectors that are connected to the digital DVI output of the video card, for the transformation of digital data stream using their own digital to analog converters, and the characteristics of the video DAC can not zavisyat.

5. Video-ROM (Video ROM) - read only memory device that records video-BIOS, the screen fonts, office tables, etc. ROM video controller is not used directly - it refers only to the central processor. Stored in the ROM-BIOS ensures video initialization and graphics card work before loading the main operating system, and the system still contains data that can be read and interpreted by the video driver in the process (depending on the method of shared responsibility between the driver and BIOS). On almost all the advanced maps installed electrically alterable ROM (EEPROM, Flash ROM), Overwrite video-BIOS personally support the user when special programki.

6. cooling system - is designed to preserve the temperature regime in the video processor and memory limits.

The video card:

Memory bus width, measured in bits - the number of bits of disk imaging, transmitted per clock. An important parameter in the performance of the card.

Video RAM is measured in megabytes - the volume of the memory card. Larger amounts are not always means greater productivity. Video card, integrated in the chipset of the motherboard or are part of the CPU, traditionally do not have their memory and use for their own use part of the RAM computer (UMA - Unified Memory Access).

Core and memory - are measured in megahertz, the more, the faster the card will process the information.

Texture and pixel fill rate is measured in millions of pixels per second, shows the information to be printed at a time.

Conclusions cards - VGA graphics cards and later tended to have only one connector VGA (15-pin D-Sub). Currently board equip the DVI or HDMI, Display Port or in an amount of from 1 to 3. Some graphics cards are equipped with the latest generation of ATi six video outputs. DVI and HDMI are evolutionary stages in the development of video transmission standard, so to connect devices to the data types you can use port adapters. DVI port is 2 kinds. DVI-I includes analog signals, allowing to connect the adapter to the monitor via the connector D-SUB. DVI-D does not allow it to do. Dispay Port allows you to connect to 4 devices including speakers, USB-hubs and other input-output devices. The video card can still be placing composite and S-Video video output and video input (denoted as ViVo)

Variety of memory cards

FPM DRAM (Fast Page Mode Dynamic RAM - Dynamic RAM with fast page access) - the main type of memory, identical to those used in residential motherboards. Uses asynchronous access, in which the control signals are not tied rigidly to the clock frequency of the system. Actively used until about 1996

VRAM (Video RAM - Video RAM) - the so-called dual-port DRAM. This type of memory accesses data directly from the 2-device, that is, it is possible to simultaneously write data to any memory location, and once this data is read from some located near the cell. In this way, allows to combine the time-image display and processing it in memory, which reduces access latency and increases performance. That is RAMDAC may have intended to display the monitor repeatedly screen buffer, did not make any video processor preventing data manipulation. However, this is the same DRAM and speed it is not very high.

WRAM (Window RAM) - variant of VRAM, with an increase of about 25% capacity and the help of some commonly used functions, such as the delineation of fonts, images and moving blocks, etc. It is used almost exclusively in the speed of Matrox and Number Nine, as requires special access methods and data processing. The presence of only one of the first types of memory provided by the manufacturer (Samsung) greatly reduced the possibility of its use. Video adapters built using the provided forms of memory, do not tend to drop in performance when installing huge resolution and refresh rate of the screen on a single-port memory in such cases all RAMDAC longer takes the bus to access memory and a video can be very productive fall.

EDO DRAM (Extended Data Out DRAM - dynamic random-access memory with an extended hold time data output) - type of memory elements pipelining, allowing multiple units to accelerate the exchange of data with video by about 25%.

SDRAM (Synchronous Dynamic RAM - Synchronous Dynamic RAM) replaces the EDO DRAM and other asynchronous single-port memory types. Once produced the first reading from the memory or the first record in memory, follow the read or write occurs with zero latency. This achieves a maximum speed of reading and writing data.

DDR SDRAM (Double Data Rate) - version of SDRAM with data transmission on two cuts of the signal, we eventually doubling the speed. Continued until the formation is in the form of another seal of packets in a single bus cycle - DDR2 SDRAM (GDDR2), DDR3 SDRAM (GDDR3), etc.

SGRAM (Synchronous Graphics RAM - synchronous graphics RAM) version with synchronous DRAM access. Basically, the service is quite similar to SGRAM SDRAM, but additional support is some special features, such as the block and of mask writing. Unlike VRAM and WRAM, SGRAM is a single-port, but it can open two memory pages as one to emulate other types of dual-ported memory.

Video card

MDRAM (Multibank DRAM - mnogobankovoe RAM) - version of DRAM, investigated by MoSys, created as a set of independent banks amount to 32 CIB each use pipelining.

RDRAM (RAMBus DRAM) memory, which uses a special data channel (Rambus Channel), which is a data bus width of one byte. Through this channel can transmit information very large flows, the highest data rate for 1 channel at the moment is 1600 MiB / s (800 MHz, the data is transmitted on two slices of momentum). One such channel can connect multiple memory chips. This memory controller operates with a single channel Rambus, single-chip logic can be placed four of the controller, so you can theoretically support up to four of these channels, providing the greatest bandwidth of 6.4 GB / s. Less of this memory - need to read the information in large blocks, otherwise its performance drops dramatically.