Load Testing
For those of you that are curious as to some of the reasoning and equipment behind our PSU testing program here at TheFPSReview, we have put together an introduction for you. This program is based on what the author developed at [H]ardOCP and utilizes the equipment bequeathed to the author by Kyle Bennett. The testing we are conducting today is exactly as described in that document and start with our 120v, 100v, Torture, and 80 Plus Tests.
120v and 100v Load Testing Results
Test #1 is equal to approximately 25% of the rated capacity of the BitFenix Formula Gold 550W at 45c. This makes Test #1 equal to 147W by loading the 12v rails to 10a, the 5v rail to 2a, the 3.3v rail to 1a, the +5vsb to 2a, and the -12v to 0.3a. The results of Test #1 show the main positive DC output rails starting at or above nominal. The efficiency for this unit is starting off in very good shape at a value of 88.60% at 120v AC input and 87.91% at 100v AC input. We see the exhaust temperature is 47C at 120v AC input and 50C at 100V AC input.
Test #2 is equal to approximately 50% of the rated capacity of the BitFenix Formula Gold 550W at 45c. This makes Test #2 equal to 275W by loading the 12v rails to 20a, the 5v rail to 3a, the 3.3v rail to 2a, the +5vsb to 2a, and the -12v to 0.3a. Test #2 sees the DC output voltages drop relative to what we saw with Test #1. The largest changes are up to a 0.05v decrease on the 12v rails, 0.02v on the 5v rail, and 0.01v on the 3.3v rail. The efficiency has moved up to 91.11% at 120v AC input and 90.22% at 100v AC input. We see an exhaust temperature of 51C at 120v AC input and 53C at 100V AC input.
Test #3 is equal to approximately 75% of the rated capacity of BitFenix Formula Gold 550W at 45c. This makes Test #3 equal to 403W by loading the 12v rails to 30a, the 5v rail to 4a, the 3.3v rail to 3a, the +5vsb to 2a, and the -12v to 0.3a. Test #3 sees another round of across the board drops. The 5v and 3.3v rails have dropped by up to 0.02v. The 12v rails have dropped by up to 0.04v. The efficiency in Test #3 moves down to 89.47% at 120v AC input and 88.10% at 100v AC input. We see an exhaust temperature of 53C at 120v AC input and 56C at 100V AC input.
Test #4 is equal to approximately 100% of the rated capacity of the BitFenix Formula Gold 550W at 45c. This makes Test #4 equal to 539W by loading the 12v rails to 40a, the 5v rail to 7a, the 3.3v rail to 5a, the +5vsb to 2a, and the -12v to 0.3a. In the final regular test, we see the 12v rails move down by up to 0.07v at 120v AC input and 0.12v at 100v AC input. The 5v rail sees a 0.12v drop at 120v AC input and 0.14v AC input at 100v AC input. The 3.3v rail is similar as it sees a 0.11v drop at 120V AC input and 0.15v at 100v AC input. The efficiency has dropped as we see it come in at 87.30% at 120v AC input and 84.03% at 100v AC input. We see an exhaust temperature of 56C at 120v AC input and 58C at 100V AC input.
Torture Test
The Torture Test is equal to approximately 80% of the rated capacity of the BitFenix Formula Gold 550W at 45C. This makes the Torture Test equal to 440W by loading the 12v rails to 31a, the 5v rail to 8a, the 3.3v rail to 5a, the +5vsb to 2a, and the -12v to 0.3a. At the end of the Torture Test, the Formula Gold 550W is still doing well. The DC output voltages are generally in line with what we have been seeing in the 120v load tests. The efficiency is very good as we see a value of 88.38% and the exhaust temperature is 59C.
80 Plus Load Testing Results
As we see here, the Formula Gold 550W posts efficiency values of 88.09%-91.04%-87.32% using 80 Plus’ load testing parameters. This puts the unit right in the 80 Plus Gold standard. However, we do use different equipment than 80 Plus for our testing and there is always a bit of component variation.
Load Testing Summary
Today, the BitFenix Formula Gold 550W did a passing job in our initial load testing. When we look at the voltage regulation, we see that the Formula Gold 550W had peak changes of 0.2v on the 12v rails, 0.17v on the 5v rail, and 0.18v on the 3.3v rail. These absolute values are in specification but the 3.3v rail does end right down at the ATX12v specification minimum during Test #4 at 100v AC input. We have not seen any other 550W entry-level units to date. However, these results do not seem like they are going to be the cream of the crop among 550W units given how close they are getting to the ATX12v limits and how large the voltage output changes were. Things do look a bit better when we look at the efficiency as that ranged from 87.30% to 91.11% efficient at 120v AC input and 84.03% to 90.22% efficient at 100v AC input. On top of that, this unit also made the advertised 80 Plus efficiency values easily. Lastly, the exhaust temperature peaked at 56C at 120v AC input, 58C at 100v AC input, and 59C during the Torture Test. Let’s move on to the Transient Load Tests.