How is display devices connected to the integrated Intel HD Graphics?

Question

Many new Intel processors have got integrated Intel HD Graphics so that there is no need to have a separate graphics card in a system with such a processor. How is a display device, such as a monitor, connected to the integrated Intel HD Graphics? Can it be connected to a display device on a system without a separate graphics card, such as a desktop computer without a graphics card?

Answer 1

The 'adapter' device is sort-of absorbed into the chipset of the system.

Look at this Intel H67 chipset diagram as an example.

1. The blue HD Graphics block is in the gray Intel Core processors block and there is a link to the PCIe Graphics block to its left.
2. The integrated graphics path goes down to the H67 block and out on its left to the Digital Display path into your monitor.
3. If you use a discrete graphics card, the processor communicates with it through the PCIe path.

This is also stated in the Intel article extract after the diagram.
_{Note that we are not referring to things like Nvidia Optimus here.}

From Intel article Common Misconceptions of Intel® Processor Graphics,

In discrete graphics devices, the graphics subsystem is contained primarily on the PCI Express bus. However, with Intel X3000, the graphics subsystem sometimes uses the CPU in addition to its own GPU resources (vis-à-vis the Graphics and Memory Controller Hub (GMCH), system memory, and the graphics core integrated into the chipset). With 3x00 series graphics, the CPU is used for the first stage of 3D processing (geometry operations), while the chipset handles the rest of the 3D processing thereby placing less reliance on the CPU. In utilizing system memory for system and graphics usage, Intel X3000 balances both resources, yielding optimal price/performance for our customers.

Answer 2

On motherboards with Intel's H67 chipset and Intel's Z68 chipset the display device can be connected to a port in the motherboard such as a VGA, DVI, HDMI or DisplayPort.

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I learned this via Do I need a GPU to use a built computer?:

Do h67 motherboards have this "integrated video chip"?

The board itself does not, but the Intel CPU's that are compatible with the socket 1155 chipset do. Every H67 based board will have a VGA/DVI port that's driven by the Intel integrated graphics.

And via Intel Core i5-2500, Core i5-2400 and Core i5-2300 CPU Review. Page 4:

The differences between P67 and H67 chipsets are quite logical. The first one is targeted for high-performance desktops, while the second one – for systems working with integrated graphics. So, H67 supports two independent monitor outs, but cannot split PCI Express x16 processor bus in two for a pair of graphics cards.

And via Intel Sandy Bridges H67, P67 and Z68 Differences Explained:

H67 – Onboard graphics are enabled, while overclocking is disabled

P67 – You need a graphics card for this chipset – onboard graphics is disabled, however overclocking is enabled here

Z68 – You guessed it…best of both worlds. Onboard graphics are enabled, as is overclocking