UPDATE (June 4, 2014): This method doesn't seem to work in OS X Mavericks. Stick with OS X Mountain Lion if you want to retain graphics support.
"Ivy Bridge" processors) uses two different types of integrated graphics cards: HD 4000 and HD 2500. Most Ivy Bridge processors feature the lower-end HD 2500.
If you want to find out whether your Intel processor uses HD 2500 or 4000, you can Google the model of your processor. For example, if I search "i5-3470" on Google, the first result is Intel's official page for the Intel Core i5-3470. According to the "Graphics Specifications" section of that page, the i5-3470 processor uses "Intel® HD Graphics 2500", which will work. If your processor uses HD 4000 graphics, check out our guide for enabling HD 4000 instead.
1. Adjust your BIOS
To make HD 2500 work in Mac OS X, you need to adjust the amount of internal graphics memory used by Mac OS X. You can do this in your computer's BIOS, which is essentially the settings page for your motherboard. Boot your computer, and enter the BIOS. To enter the BIOS on a Gigabyte motherboard, you have to press the delete key when it boots (before the operating system starts). Different manufacturers set different keys for opening the BIOS.
The specific name of the BIOS setting that you need to change depends on the brand of your motherboard. On Gigabyte motherboards, this setting is literally called "Internal Graphics Memory Size".
2. Adjust settings for Chimera
UPDATE (September 23, 2013): Chimera bootloader has added built-in support for HD 2500. So in theory, this step is no longer necessary-- just make sure to install Chimera version 2.2 or newer (which is included in new versions of Unibeast & Multibeast by default).
At this point, Mac OS X still won't recognize your Intel HD 2500 integrated graphics. Even though Mac OS X now includes drivers for HD 2500, these drivers don't work on Hackintoshes by default. To fix this, boot into your Hackintosh. Open up Finder, go to /Extra in the main hard drive, and open the file org.Chameleon.boot.plist with TextEdit. Between <dict> and </dict>, insert the following line.
3. Install the "Mac mini" system definition
As a final touch, you will need to install the Mac Mini system definition. Open Multibeast, and select the following option.
- The VGA port on your monitor will not work (real Macs don't have VGA ports). You have to use either the DVI or HDMI port on your monitor.
- If you have turned off GraphicsEnabler, you will have to re-enable it. You can do so by reopening org.Chameleon.boot.plist (from Step 2), finding the "GraphicsEnabler" section, and changing "No" to "Yes" (without quotation marks).
- The maximum resolution that HD 2500 can display through the DVI port is 1900x1200. The maximum resolution that it can display through the Displayport is 2560x1600. These limitations apply to all operating systems, not just Mac OS X.
SOURCE: [Guide] Intel Ivy Bridge HD2500 Full Resolution and QE/CI (10.8.3+)