can i use this to power a pcie x16 card in a pcie x1 slot
I doubt it will provide full power. You care better off using a PCI-Express x 1 video card, forget about x16...
That depends on what you mean by 'power'. You can use it to connect a PCIe x16 card to a PCIe x1 slot but it'll only have one PCIe lane connected, meaning that the interface will only have 1/16th of the bandwidth. That's fine for something like using a graphics card to mine Litecoin but not for gaming. As for powering it, if the card uses a lot of power so has external power connectors like a graphics card then you still need to connect those, if it normally runs without an extra power cable then it'll be fine. You'll notice that most of the reviews there are from people who were building Bitcoin/Litecoin mining rigs. When doing that the graphics cards are working flat out but there's not a lot of data being sent through the interface so a x1 interface is fine, when gaming the interface has to carry a lot more information so this would really slow it down. It would be fine for just providing a way to plug in a cheap graphics card to provide a second display for normal 2D use though but its 3D performance would suffer.
