The unit maintains the stability of the +12V rail well enough, but performs worse at high loads on the +5V rail. The PSU couldn’t even make it to the maximum load of 200 watts because the voltages go beyond the required ranges even at 150W on this rail. Like with the previous models, the +3.3V voltage varies rather much depending on the load.

The ripple of the output voltages has become a little stronger if compared with the previous models. This is natural since the ratings of the output filters of this PSU are the same as the ones in the ISP300 series models, while the load is higher here. Still, the ripple is always within the norm.

This power supply also changes the speed of its fan with a sudden jump at about 170W load power. It’s hard to call this PSU quiet when the fan is at its maximum speed of 2000rpm.

The efficiency of this power supply is the same as that of the above-described ISP300A2-0.

So, this PSU is in fact a higher-power version of the IW-ISP300 models with a 12cm fan (again, the real wattage of this power supply is 300W rather than 350W). The parameters are good, but the unit isn’t quiet even in low-end computers – if the load is above 170W, the fan spins up immediately to its maximum rotational speed.