Efficiency, Differential Temperature and Noise
Efficiency
Efficiency is defined by the power output divided by the power input and is usually expressed as a percentage. If a PSU were a 100% efficient (which none are) 750 watts of AC power going in would result in 750 watts of DC power coming out (with no waste heat to dissipate). In the real world there are always inefficiencies and power is lost in the form of heat during the conversion process. Newer revisions to the ATX12V Power Supply Design Guide V 2.2 have continued to increase the efficiency recommendations for PC switching mode power supplies and now lists both required and recommended minimum efficiencies.
We measured the AC power input to the PRIME Ultra 750W Titanium PSU with an Extech power analyzer while the total DC load was found by adding all the individual +3.3V, +5V, +12V, -12V and +5VSB loads together.
The overall efficiency of the PRIME Ultra 750W Titanium power supply is excellent and meets the criteria for 80 Plus Titanium certification, even while operating on 120 VAC and at elevated temperatures.
80 Plus Program
Note: Tests conducted at room temperature (25°C)
Differential Temperature and Noise Levels
To simulate a demanding environment, some of the warm exhaust air from the PSU under test is recirculated back to the intake through a passive air duct, which allows the PSU air inlet temperature to increase with load, just like it would in a real PC.
The differential temperature across the power supply was calculated by subtracting the internal case air temperature (T in) from the temperature of the warm exhaust air flowing out the back of the power supply (T out).
Thermocouples were placed at the air inlet and exhaust outlet. The ambient room air temperature was 23ºC (74ºF) +/- 0.5ºC during testing.
T out = temperature of air exhausting from power supply
T in = temperature of air entering power supply
Delta T = T out – T in
Sound pressure level readings were taken 3’ away from the rear of the case in an otherwise quiet room. The ambient noise level was ~27 dBA. The power supply was tested with Hybrid Fan Control turned On (enabling fanless operation at low to mid power levels).
*Fan not spinning
The PRIME Ultra 750W Titanium PSU cooling fan did not start spinning until we hit the 75% load mark. At this point the fan noise was still very quiet and even at the 100% load mark the fan noise stayed relatively quiet. Having great efficiency helps keeps the waste heat and fan noise to a minimum.
(Courtesy of Seasonic)
I just wonder how are you
I just wonder how are you going to clean, while still keeping it under warranty, something that has a 12 year warranty.
I have an original Prime 650
I have an original Prime 650 (not Ultra) and would like to know specifically how they differ.
It would seem the Ultra is just a Prime, with a couple of meaningless upgrades. Is this true?
Yes, as we said above, the
Yes, as we said above, the Ultra is an upgraded PRIME. Along with some minor tweaks to the design (Seasonic does not specify exactly what) the main difference is the longer 12-year warranty – I wouldn't call that meaningless. If you have an original PRIME you should be well served for many years to come.
They did specify it, when
They did specify it, when they released upgraded Ultra line. See:
https://seasonic.com/news/post/prime-ultra-power-supplies/
Are the PSUs really that
Are the PSUs really that quiet? Basically not audible, quieter than the room? My computer’s fan go at 450RPM and I have no HDDs to make spinning noises anymore.
Yes, they are very quiet. But
Yes, they are very quiet. But sound/noise is subjective. Even though the SPL numbers are hard data different people respond differently to sound. To my ears, this PSU was very quiet – silent until the fan kicked in (no coil whine or electro-mechanical noise). The test lab is relatively cool and quiet (fairly constant 73 deg and 27 dBA) – to the point I opt to turn off the building A/C air handler during testing. Both the background temp and sound level will contribute to your experience of how loud a system is. Hope that helps answer your question.