Zalman ZM750-HP Power Supply Review
Overload Tests
Contents
Before overloading power supplies we always test first if the over current protection (OCP) circuit is active and at what level it is configured.
OCP kicked in when we tried to pull more than 24 A from +12V2 input from our load tester (which was connected to the power supply +12V1 through the ATX12V/EPS12V cable). The label says that each rail has a limit of 20 A, so OCP was configured the way we like: close to the limit printed on the label.
Below you can see the maximum values we could pull from this power supply. If we tried to pull more than that the power supply wouldn’t turn on, showing that one of its protections was in action, which is terrific.
| Input | Maximum |
| +12V1 | 33 A (396 W) |
| +12V2 | 24 A (288 W) |
| +5V | 18 A (90 W) |
| +3.3 V | 18 A (59.4 W) |
| +5VSB | 2.5 A (12.5 W) |
| -12 V | 0.8 A (9.6 W) |
| Total | 851.6 W |
| % Max Load | 113.5% |
| Room Temp. | 49.8° C |
| PSU Temp. | 50.9° C |
| AC Power | 1,040 W |
| Efficiency | 81.8% |
As you can see even during this extreme condition efficiency was above 80%, which is nice. And, like we mentioned, the power supply won’t burn if you try to pull more than it can handle: it will simply shut down.