what are the make and model of the power supplies? prebuilt pcs often cheap out on power supplies which cause trouble later on. i am not saying these have bad psus, but you should make sure, since these are using high power consuming parts.
if possible, you should build the pc yourself with clearly chosen parts. or have someone trustworthy build it for you.
the ram (system memory) seems underpowered at ddr3 1333. it's not 1600 MHz as it says. i mean that it could be either but the label is contradictory.