So now we're going to test the Core Edition 450W. To do this, we use a SunMoon SM-8800 active load tester. There are 10 loads. The first eight are programmed to represent 10%, 20%, 30%, 40%, 50%, 60%, 80% and 100% loads. Then there are two "cross loads" that put either a massive load on the non-primary rails or just the +12V rail. "Test 0" is nothing more than the PSU plugged into the load tester while test 1 is active, but the power supply is "off" (in stand by) so only the +5VSB has a load on it.

At each test, I measure voltage, total wattage at the PSU as well as at the wall, calculate efficiency. measure power factor and measure intake and exhaust temperatures.

The first round of tests are done in open air. Therefore they are called "cold tests".

First things first, does the Core Edition pass 80 Plus Bronze, which requires at least 82% efficiency at 20% and 100% loads and 85% efficiency at 50% load? Well, at 20% load we got 81% efficiency, but units can vary slightly from one to another so I'm willing to say that this is "close enough" to say that another sample in an another environment could have achieved 80 Plus Bronze efficiencies.

The other thing to note is how high the +12V rail is. It's hard for me to explain what exactly is going on here. Certainly, there is some sort of +12V sense circuitry going on here, but not like the old school +3.3V sense circuitry that sent a sense wire down to the connector to measure the actual voltage of the +3.3V so an IC within the PSU could adjust accordingly. At first it would see that something is just sensing load, and not actually monitoring voltage, and proactively adjusting the voltage upward to compensate for any kind of drop. That would be a fine idea, if the voltage wasn't actually being increased .01V for every 50W of load! And then, when you see the +12V voltage during CL2, you have to throw that whole theory out the window when the total load is only slightly more than what's performed during test 7 and the voltage drops all of the way down to 11.79V? Excuse me, but "what the hell"? And then have a look at CL2. The loads on the +3.3V and +5V are at 14A each and there's only a 2A load on the +12V and the +12V increased to 12.68V!

It just doesn't make sense to me. I mean, if this PSU uses DC to DC like the box states, then the +3.3V and +5V are being converted from the +12V, so a load on either of those rails is also a load on the +12V rail. So any load on any of those three rails is going to be read as a load on the +12V. Maybe I'll figure this all out when I open the unit up.

Wow... anyways... moving on. We also measure ripple and noise using a USB Instruments Stingray Oscilloscope hooked up to the SunMoon tester. Below are the results from that Oscilloscope.

Oscilloscope Measurements for XFX Pro 450W
Test #	+3.3V	+5V	+12V	+5VSB
Test 1 (+5VSB Only)
Test 2
Test 3
Test 4
Test 5
Test 6
Test 7
Test 8
Test 9 (CL 1)
Test 10 (CL2)

As we can see here, there's nothing at all alarming with this units ability to suppress ripple and noise. I have to admit the +5SB looks a little funky at times (test 4 to 8). Not bad and certainly well within spec, but when I saw the waveform, I immediately thought that this is what the waveform would look like if I were measuring the audio from a Tuvan throat singer like Kongar-ol Ondar. Ok.. maybe not. But I did think about it for a minute or two.

Now let's put a lid on things... not literally... ok, maybe literally.... we now pump the heat from the load tester into a wood box that the power supply will suck air in from. Being that this is a 450W power supply, I don't expect it to generate much heat, just as a PC that only requires a 450W wouldn't generate much heat (it can't. It can only use up to 450W of power!), but since some power supplies are rated at room temperature while others, like this XFX, are supposedly rated at up to 50°, we need to see if any heat will make this power supply perform differently.

During test 7, I actually said "holy crap, that's loud." Despite the noise of the loud noises of the SunMoon load tester, I could hear the 120mm fan of the XFX Core Edition 450W spin up and become the loudest thing in the room. Of course, this fan noise didn't go away during test 8 as things only got hotter, but once I entered out of test 8's load and into CL1, I can actually hear the fan spin down after about 2 minutes. Then, when I kicked in the CL2 load, the fan started to spin up again after about 30 seconds.

Performance wise, the power supply didn't really perform any differently hot versus cold outside of the fan speed. That's good in that it did hold up to the high heat just fine. That's bad because the +12V regulation is still crazy wack funky.

Now let's open up the PSU and see what's inside...

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