The more advanced (400W) model from Zalman comes in a comely black box. The dimensions of the box as well as its contents are practically identical to the package of the ZM300A-APF: a PSU, a user’s manual, a power cable and a ZM-MC1 adapter for attaching system fans.
You should be aware that despite the high claimed power, only the maximum current on the +5V bus exceeds that of the above-described model (40A against 30A), while other characteristics are identical. So if your computer system has problems with the overloaded +12V bus, you can’t solve them by installing a ZM400A-APF instead of the ZM300A-APF. That’s because the ATX standard clearly defines recommended allowable currents for PSUs up to 300W (30A on the +5V power bus, 28A on the +3.3V power bus and 15A on the +12V power bus). If the PSU has a higher wattage, each manufacturer chooses his own way: some increase currents on all buses, others do this for one or two buses only. By the way, I’m talking about high-quality products now, as low-end PSUs often have “paper” characteristics, which don’t necessarily coincide with their actual capabilities.
The PSU seems to be different from the above-described model, but this impression is only due to the black color of the case. In fact, the ZM300A-APF and the ZM400A-APF have absolutely the same cases.
The PCB now carries the name of Zalman, but this label shouldn’t confuse you: the internal structure of the unit is not absolutely identical, but very close to the ZM300A-APF, which is manufactured by FSP Group. It is of course possible that Zalman is producing these units in its own facility under a license from FSP, but not very likely. The habitual letters “SPI” (SPI Electronics is a member of FSP Group) are written on the power transformer of the PSU. I don’t have exact data about how the ZM400A-APF fits into the model range of FSP Group, but it’s quite logical to suppose that it is a closest relative of the FSP400-60PFN.
This unit has a more respectable look in comparison to its lower-wattage predecessor. The filtering capacitors have increased their power (the input high-voltage rectifier now uses a 330uF capacitor – double capacitance compared to the ZM300A-APF. I couldn’t make out the capacitance values of the output rectifiers, as all components are very tightly packed in the unit, but their larger dimensions indicate certain changes). The T-shaped heatsinks also have impressive dimensions: the thickness of the vertical pole is about 4-5mm, while the horizontal line is one millimeter wider. Small and thick ribs cover both parts of the heatsinks and the whole construction provides efficient cooling of the transistors and diode assemblages.