Help with understanding x16 vs x4 on motherboard?

[Guest]

Okay, so I asked about SLI not too long ago, and got an answer, but it brought up another question:
What is the difference between x16 and x4? My motherboard (http://www.gigabyte.com/products/product-page.aspx?pid=3908#ov) has two PCIe slots, one saying it is x16 running at x16, and the other is x16 running at x4.

I've tried researching myself, but I'm not getting any good answers that I understand. Currently, I'm pretty sure I have my GTX 670 plugged into the slot running at "x4" (due to space reasons). Am I not getting the full power of my card because of this? And will I be able to run two GTX 670s in SLI at all on this motherboard? What real difference does a x16 make against an x4?

 

[lonewolf7]

The real difference is bandwidth. You can have plenty of answers by reading(technical aspect) : https://www.google.co.in/webhp?sourceid=navclient&hl=en-GB&ie=UTF-8&rlz=1T4GGNI_en-GBIN533IN533&gws_rd=cr&ei=ubhNUsbOHoHRrQfGrIFw#hl=en-GB&q=difference+between+x16+and+x4+pcie

The simple thing is x16 will use the full bandwidth of GPU and will run as it should be(faster). And x4 will limit the bandwidth of GPU and will run somewhat slower.

So try to use the GPU on x16 slot and get full use of it. Good luck.