When Choosing Graphics Processor (GPU) figure out how many screens you want. On the back plate of GPU and in specs, see how many  HDMI, mini HDMI (cheap mini hdmi to HDMI adapter), and DVI. Make sure to see what connections your monitors have. Now find GPU with that amount of screen hook ups you need. Look at clock speeds (MHz) find one with a good clock. Some GPU's are already Factory Overclocked & say "OC" or "SC" (Overclocked or SuperClocked) GPU comes with easy to use Overclocking Software anyways. Next make sure you get one that has at least 2GB Memory. When you pick one out, check specs on GPU's Length & check your computer case specs to see Max Length of GPU's that will fit in that case. Gigabyte GTX 750 Ti  GDDR5-2GB 2xDVI/2xHDMI OC Graphics  can run 4 monitors and high clock speed, and only around $140. The GTX 750 Ti graphics card comes in many brands like ASUS GeForce GTX 750Ti runs 4 monitors real High clock and only about $125 you just need to check monitor connections on GPU. You can find GPU's under $100 Just browse pages, read and check specs on componets once you find all parts you need putting it all together isnt hard.