You're running 4 overclocked 290 off a single 1300w? Supernova PSU's are great, but overloading them over 100% just isn't safe for the PSU, nor the motherboard.
Actually the 290s are not overclocked and the 1300 provides just enough power, the rigs run 100% stable with 0 issues, temps stay under 82 as well. I have a 3rd identical rig like this that has ran for about 2 months straight very solid.
If anyone on here is actually interested PM me, price can be negotiated further. Also open to a trade for some antminers.
FYI, rigs can mine N-scrypt / Vertcoin at ~1.7MH/s as well...