The placard shows that the eXtreme Power 600W uses a pair of 12 volt rails which is fast becoming the standard in good power supplies, yet there are still some power supplies like those you find that come with some low-end computer cases that only use one 12 volt line. They should really not be trusted with your expensive new gear especially if your motherboard calls for a 24-pin power connector. The eXtreme Power 600W has the option of using either the 24-pin or the 20-pin configuration depending the motherboard you are going to use the power supply with.

The fan used on the eXtreme Power 600W is made by a company by the name of Globe fan Incorporated, I was able to find this information able the fan on their web site.  With a maximum RPM rating of 2800 and a maximum CFM of 94.92 I can see why Cooler Master chose not to use a fan at the rear of the power supply.

RATED VOLTAGE	OPERATING VOLTAGE	RATED CURRENT	STARTING VOLTAGE	RATED INPUT POWER	MAX AIR FLOW	MAX STATIC PRESSURE	NOISE	RATED SPEED
(V)	(V)	(A)	(V)	(W)	(CFM)	(mmAq)	(dBA)	10%
12	6-13.8	0.52	6	6.24	94.92	7.13	43.6	2800

Here is a chart that represents the speed of the fan in comparison to the amount of power that the power supply is putting out.  Cooler Master calls this their Intelligent Fan Speed Controller and during our testing it did seem to ramp up the speed as the need for more power from the power supply was called for.

Looking at the in workings of the power supply I have to admit I was a bit surprised by how small the heatsinks were as well as how much room there was left inside the case itself.  This is the first 600 watt power supply that I have ever reviewed that  about 1/4 of the rear of the supply clear of any components.  I first thought perhaps they left something out.  We will find out shortly just how much of a difference this makes as we get ready to stress the unit and see how well it handles what we can throw at it.  Oh yes before I forget, a very nice manual is included with the power supply.