ASUS “Vento” U-75HA (750W)
The 750-watt U-75HA will complete this review.
Its box is larger and heavier than the boxes of the previous models. Two model names are indicated on it in large print: U-75HA and U-65HA. You have to look at the table on the side panel to learn what exactly model is hidden within.
The PSU itself is larger, too. Its length is 180 millimeters as opposed to the previous models’ 140. Well, I don’t think anyone would try to install a 750W power supply into a microATX system case, so the large size shouldn’t be a problem.
There is no free space inside. The PCB occupies the entire case. The power supply is equipped with active PFC and, unlike the previous models, features dedicated voltage regulation. You can see this by the three (instead of two) large toroidal chokes in the low-voltage section (the top right of the photograph).
I have no complaints about the assembly quality of this model, either. Everything is neat, the cables are tied up with straps, and large elements are secured with drops of glue.
Widely reputed KZH series capacitors from United Chemi-Con are installed at the PSU’s output. Expensive PSUs make use of the KZE series as a rule, but the KZH series differs with even lower equivalent resistance, which means better filtering of high-voltage pulsation.
One component draws your attention with a loud click whenever you turn the PSU on or off. It is an electromagnetic relay capable of switching up to 250VAC at a current up to 16A.
The relay helps reduce the power consumed by the PSU in idle mode. Although the main regulator is shut down then, the active PFC device of a computer PSU goes on working uselessly, consuming some power. But PFC is not necessary at all for idle mode because the +5V standby source is powered directly by the mains.
To avoid this loss, the U-75HA has a relay in its high-voltage section right before PFC. This relay can disable the PFC device when necessary.