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Cooler Master iGreen Power Series
Power Supply Units | First Looks
Fri 24 Mar 2006

Gone Green


The light indicator will tell users if something bad has happened to their PSUs.

Perfect for SLI or CrossFire: two PCIe power connectors are specially provided.

396W for the +12V rails should be more than enough to power a multi-GPU rig.

In recent years, we have seen a prodigious leap in power requirements for PCs.  Multi-core processors are been pushed aggressively by chipmakers while the graphics subsystem has also grown more power hungry. Dual graphics cards configurations using NVIDIA's SLI or ATI's CrossFire are quite popular among enthusiasts and the ante has been upped with Quad SLI systems equipped with four high-end graphics cards. The near future could well see such multi-GPU systems becoming the norm.

These developments are the underlying reasons for the features found in the new iGreen Power series of power supply units from Cooler Master. Rated at up to 85% efficiency for a load of 250W, it claims to be extremely silent while being ready for SLI and CrossFire. Here are our initial impressions based on the 500W model in the series: 

Efficiency is King

A PSU with high efficiency generates less residual heat, meaning that manufacturers can afford to use slower spinning PSU fans to cool the unit, resulting in a quieter and cooler PSU. The efficiency of the iGreen Power series may vary under different loads though based on its specifications, it should remain above 80% for most situations. Its peak efficiency is listed as 85% at 250W, which is quite appropriate, as most systems would probably be drawing around that amount under normal conditions. For those concerned with the strength of the +12V rails, the 500W model provides a combined total of 396W with the peak current for each rail topping off at a respectable 19.5A.

The dual ball bearing 120mm smart fan spins at around 800RPM at 50% load, though it is programmed to ramp linearly up to 2300RPM as the load increases. The noise generated by this fan ranges from 17dB to 28dB, so while Cooler Master will no doubt emphasize the lower 17dB rating, it may not always be the case. Nevertheless, reaching 28dB is probably a rare occurrence and even then, it should still be a relatively quiet one for most users.

Multi-GPU Support

As SLI and CrossFire configurations are more prevalent nowadays, it is quite common to find multi-GPU certified power supplies from manufacturers. The Cooler Master iGreen Power comes with two PCIe power connectors specifically catered for higher end graphics cards, which usually requires more power. A quick check with NVIDIA's official SLI Zone website revealed that the iGreen Power series (both 500W and 600W models) are indeed certified for SLI, but isn't listed for a dual GeForce 7800/7900 GTX configuration. Of course, SLI Zone is but a guide and NVIDIA is likely to be conservative in its testing so you probably could run two GeForce 7900 GTXs safely using an iGreen Power PSU. After all, proper qualification will of course take time and the iGreen Power is a brand new series.

Pampering End-Users

The iGreen Power series has been rated capable of more than 400,000 hours of operation and a built-in power failure detector will light up to warn users of failures like short circuits, overloading and overheating. All the cables are sleeved to enable easy and neat maintenance and should also contribute to improving airflow in the casing. Unfortunately, while other manufacturers have introduced modular products where unused cables can be removed, this useful feature is not found in the iGreen Power series. Hopefully that can be added in a later revision of the series.

Final Thoughts

Cooler Master's new iGreen Power PSU series looks to live up to its environmental branding with excellent efficiency that matches up to existing competition. Compliance with a variety of standards from the newer RoHS (Restriction of Hazardous Substances) to Energy Star makes this a truly 'green' product while sufficient power is ensured by its adherence to Intel's latest ATX 12V 2.2 revision. Quiet and cool, it is certainly a state of the art power supply and with the top model rated at 600W, enough to power all but the most demanding systems and tasks.

Product Specifications
  • ATX Form Factor 12V V2.2 / SSI standard EPS 12V V2.91
  • Dimension: Standard ATX PS2 150 x 140 x 86mm
  • Dual ball bearing 120mm fan
  • Supports SLI & CrossFire
  • PFC: Active PFC (0.99)
  • MTBF: > 400,000 hrs
  • Operation Temperature: 5 - 50 degrees
  • Input Voltage: 90 - 264V
  • Input Current: 10A@115Vac / 5A@230Vac