Regarding the PSU, I contacted Enermax to inquire about the ERV1000EWT-G. I asked:
(1) What is the expected MTBF for this PSU if placed under a 85% or 90% load continuously?
(2) What is the maximum recommended continuous load for this PSU?
This is the response I received:
1. We do not have figures for MTBF at 85% or 90% load, but similar calculations show that at 100% load, the MTBF will be 42% less than in 70% load.
2. 1000W. Yet please note that the best efficiency of this power supply is at 350~600W load range. If system is constantly run at 800~1000W, we recommended to use 1500W PSU for best power consumption consideration.
Of course, the one caveat is that I do not know for sure that this is the exact model of PSU being used in the S2.