When it comes to testing a power supply, or five of them in this case, there are a lot of choices in how to tackle the job. I have found that while a multimeter can give scads of data, most of us don't have a clue what all these facts and figures mean. Even the elite of the enthusiast crowd doesn't always keep up with the inner working of a power supply. So what do we do?
Since a majority of our readers tend to be deeply into overclocking their systems, why not run these power supplies on a hot system and then stress it out? After we get things worked up nicely by running 3DMark loops and burning CD disks, we'll take a reading of the power levels right in the middle of this mess. This ought to give us a workable answer as to whether or not these products can give us the power we need under stressful conditions. If it can give solid results under this type of operating condition, it will let us know that it can handle the regular chores that we are likely to throw at it.
So lets start off with a look at the test rig:
Soltek 75MRN-L Motherboard (nForce2 chipset)
Athlon XP 1700+ @ 2.1GHz
Cooler Master X-Dream SE HSF
2x 512MB Crucial PC2700 DDR
Sapphire Radeon 9700 Pro
D-Link 10/100 NIC
TDK 52x CD-RW
Pioneer 16x DVD
Western Digital 80GB 8MB Hard Drive
Seagate 40GB 2MB Hard Drive
Sony 3.5" Floppy Drive
5x 80mm case fans
1x 120mm case fan
All right then, the processor is running at 1.7v, the memory is at 2.7v and the AGP is at default. The system is overclocked and the video card is known to cause weaker power supplies to cringe in terror. Add the stress and we should get a fair look at what these warriors are capable of.
As a final note, most manufacturers claim a leeway of +/- 5% of any given output level. Using this as a common ground, we should end up with rail voltage levels of 3.135-3.465v on the 3.3v rail, 4.75-5.25v on the 5v rail and 11.4-12.6v on the 12v rail. Keep this in mind when we go through the numbers below. Higher values can be beneficial, lower values bear watching.
Results - Raidmax 400
Considering the stress that we have been playing with during the testing phase, the numbers above aren't too bad. The 5v rail shows a bit of an increase, but still well within the limits set. That 3.3v rail bears some watching, however, as this will be where your video card gets it power from. Considering that the Radeon cards have a supplemental power connector for a 12v Molex, there shouldn't be a sharp decrease like this.
It is looking as though this PSU is getting close to its limit in our test. Considering that I don't have any lighting or alternative cooling in place, this could be cause for concern.
Results - Raidmax 500
Now we're talking! Every value above is well within that 5% margin we talked about. Even under stress, this PSU seems at ease with the workload.
Results - SilenX 400
This is interesting. While still well within the 5% margin, every value for this model is above the rated power levels. Since this is a loaded system when measuring these voltage levels, we can see that we may have a little boost when it comes to overclocking. This one looks promising, especially for a PSU that is rated at just 400 watts!
Results - Thermaltake Purepower 480
Being a larger capacity PSU, I had expected this model to handle the stress, but we see that this one too has all values on the plus side of the 5% margin. This unit shows a lot of promise for the avid enthusiast who is looking for a new means of powering that monster rig.
Results - Vantec ION 400
The Vantec unit seemed to be striving for perfection in out tests. The 3.3v rail was dead on and the 5v rail was just a shade over. And while the 12v rail is under the rated power level, it is still well within our 5% margin. Overall a very good showing.