Guys, thanks for the hints and answers. I have a question. My motherboard doesn't have any PCI Express 3.0. Only 2.0 Both R7 260x that I tested was PCIE 3.0. I didn't noticed that my motherboard didn't got PCIE 3.0. The weird part is that I got video normally even that both graphic cards were 3.0. Does PCIE 3.0 works on PCIE 2.0 slots? What this means after all? I thought it was like the DDR versions of a RAM Memory. DDR1, DDR2, DDR3 for example. But as I said before, both gave me trouble. The one from XFX do random freezes and video crashes and even a BSOD on YouTube. The one from ASUS gave me thoses random system freezes. The last freeze that I got I wasn't using the audio from hdmi, but I was using the hdmi video, and, after a few hours, BOOM, the whole pc got frozen. So... PCIE 3.0 graphic cards should work on a PCIE 2.0 16x?