nope, the x850 series is ATI which would require crossfire technology, not SLI which is for nvidia. as for the mobo choice, it should say just SLI but reading father down it should talk about it being 16x on both slots. as for the making it part, lots of guys on here could guide u through the build some day on msn if you needed help, thats how i built mine. only tip it discharge static electricity as much as possible, dont shuffle around to build up static, and pretty much theres one hole for one thing, not like u can fit a video card into a ram slot