A 10% difference in efficiency at 500w running 24/7 will save you $7/mth at $0.20kw/h
thats how much I pay for power and is why I went for a platinum rated psu
i have pretty much the same PSU as you. TX650 v1
Its been rock solid for me for the past 5-6 years even running cpu/gpu OCed @100% for weeks non stop, right now im running whats in my sig.