Swapped out my Antec Earthwatts 430w Green (80+ Bronze rated) for this Sparkle unit.
Antec 430w:
+3.3V@20A
+5V@20A
+12V1@17A
+12V2@16A
-12V@0.8A
+5VSB@2.5A
Sparkle 400w:
+3.3V@16A
+5V@16A
+12V1@18A
+12V2@18A
-12V@0.3A
+5VSB@3A
~
Power figures, measured at the wall:
Vampire power
Antec - 1.6w
Sparkle - 0.9-1.1w
Idle (at windows desktop)
A - 39.4w
S - 37.4w
CPU AVX loaded
A - 101w
S - 98w
CPU AVX + VGA Furmark loaded, measured after 15 seconds
A - 215w
S - 201w
CPU AVX + VGA Furmark, measured after 15 minutes with the case side off
A - 235w
S - 223w
CPU AVX + VGA Furmark, measured after 45 minutes with the side on
A - 244w
S - 223w
12v rail measurements:
Idle
A - 12.02v
S - 12.12v
CPU + GPU load
A - 11.81v
S - 11.94v
CPU + GPU, measured after 15 minutes with the case side off
A - 11.76v
S - 11.92v
CPU + GPU, measured after 45 minutes with the case side on
A - 11.72v
S - 11.92v
In my case, the power supply is the only exhaust, and frankly, the 80mm fan in the Antec unit was not up to the task under extreme (and very uncommon) loads, because temperatures would continue to climb inside the case over a period of 30-40 minutes. As intake temperature climbed, the power supply would warm up, rails would droop, and efficiency would go down. The Sparkle's 120mm fan and greater efficiency fare much better here, with case temperatures now being barely above ambient with Prime + Furmark.
400w is probably overkill for my uses. Even under power-virus loads on both VGA and CPU, I'm still only around 50% of its rated power, which hurts efficiency. At idle I'm somewhere in the range of 5-8% of its rated power. Under typical gaming loads, I expect it's somewhere close to 33%.
One downside to the new unit, though, is that due to the airflow layout of my case, my video card gets nearly 10c warmer now than it did before, which is encouraging me to install a fan in the side panel to keel it cool. The Antec unit drew in air from the back of the unit (top of the case) while the Sparkle draws it from the side.
If we assume a 2w savings approximately 22 hours per day, and 15w saved 2 hours per day, this power supply will pay for itself in power savings in approximately 6 years.