Zalman ZM600-HP is a 600 W power supply featuring a big 120 mm fan, an internal heatsink with a heat-pipe and modular cabling system. This unit is internally identical to OCZ GameXstream 700 W (the only difference between the two is the use of a heatsink with a heat-pipe and a modular cabling system on Zalman’s model. Let’s take an in-depth look at this power supply and see if it can really deliver 600 W or even 700 W.
ZM600-HP features high-efficiency and active PFC. According to Zalman this power supply has an efficiency up to 84% under 230 V, meaning less power loss – an 80% efficiency means that 80% of the power pulled from the power grid will be converted in power on the power supply outputs and only 20% will be wasted. This translates into less consumption from the power grid (as less power needs to be pulled in order to generate the same amount of power on its outputs), meaning lower electricity bills. Of course we will test to see the actual efficiency from this power supply under several different loads.
Active PFC (Power Factor Correction), on the other hand, provides a better usage of the power grid and allows this power supply to be comply with the European law, making Zalman able to sell it in that continent (you can read more about PFC on our Power Supply Tutorial). In Figure 1, you can see that this power supply doesn’t have an 110V/220V switch, feature available on power supplies with active PFC.
Zalman is making a terrific job by explaining on the product box what makes this power supply different from other high-end models internally, like the use of two rectifying bridges, the use of three transistors on its active PFC circuit and four rectifiers on the +12 V output and a heatsink with heat-pipe to cool down the secondary rectifiers. All that is true, as we will show later.
This power supply uses a very good cooling solution. Instead of having a fan on its back, its fan is located at the bottom of the unit, as you can see in Figure 1 (the power supply is upside down). A mesh replaced the back fan, as you can see. Since the fan used is bigger than fans usually used on power supply units, this unit is not only quieter than traditional power supplies, but also provides a better airflow.
In Figure 2, you can see this power supply modular cabling system, used by its peripheral cables. Modular cabling system is great to help the PC internal airflow and organization, as you only need to connect the cables you will really use, so no unused cables will be hanging inside the PC. On this figure you can see that the plastic sleeving used by the main motherboard cables comes from inside the power supply, which is something we always point out that manufacturers should do. On Figures 3 and 4 you can see the peripheral cables that come with this unit.
As you can see, the cables use a plastic sleeving that improves the PC internal airflow and helps cables to be more organized. All peripheral cables come with a Velcro strap, helping you to organize the cables inside your PC.
This power supply comes with six peripheral power cables: one 6/8-pin PCI Express auxiliary power cable, two peripheral power cables containing two standard peripheral power connectors and one floppy disk drive power connector each, one peripheral power cable containing three standard peripheral power connectors, two Serial ATA power cables containing three SATA power connectors each and one “Y” adapter for connecting fans to any standard peripheral power cable.
This fan power adapter is really interesting, as it provides two connectors, one connected to +12 V (full speed) and the other connected to +5 V (low speed). So you can easily change your fan speed.