- If not troubled by a few extra pounds get a 2x 4 gb kit, that way you can enjoy 1-2% faster ram in dual channel mode. Also when booting up remember to set the 1600 mhz in BIOS, otherwise it will adjust the ram at the 1333 mhz default of the motherboard.
- The psu looks like a very cheap one. In any case, it states as being able to deliver only 22 ampere on the 12 volt line, where the R9 290 requires a psu that can feed it 31 ampere. You will need another psu, this one will not work (it might be able to boot the system but it will crash or worse when being put under load).
edit: typo.