Antec Strictly Power VPF550 Power Supply Review

by - 5 years ago


Introduction & Packaging


Antec produce some of the most popular PSUs on the market, their PGS series has been a popular choice for many years now and their more recent EDGE series are winning people over too. Of course, not everyone has the budget, or the technical need for a high-end gaming PSU and that’s where the VPS550 comes in. This is a low to midrange power supply, offering 80 Plus Bronze efficiency, 550W of power, non-modular cables and a very affordable £40 price tag. Sure it’s not that exciting, but a budget-friendly gaming system or office computer will no doubt be an ideal target for Antec’s latest.

The packaging is nicely designed, showing all the main specifications right on the front, including the support for Haswell, active PFC and continuous power.


The same details are on the back of the box, as well as the multi-language breakdown.IMG_1469

In the box, you’ll find some warranty information, four mounting screws and the AC power cable.



A Closer Look – Exterior

Power Supply Unit

It’s a fairly standard looking PSU, nothing fancy, but it is quite compact, so it’ll be well suited to some smaller Micro-ATX chassis. There’s a good amount of ventilation in the top and an Antec branded 120mm fan installed for cooling.


The other side is just a blank panel, nothing fancy, but nothing out of the ordinary either.


The main specification sticker on is on the side of the PSU, showing us what we have two +12V rails, with 30A on each. This isn’t a huge amount of power, but it’s more than enough for a mid-range GPU configuration.


A good amount of ventilation at the back, as well as the AC line-in and the master power switch.



The cables are about as basic as you could expect, all hard-wired, with only the 24-pin featuring any braiding. There’s a pair of 6+2 pin PCI-E cables, as well as a mixture of Molex, Sata and a Floppy connector.



A Closer Look – Interior

Wow, there really isn’t a lot of hardware inside here, although I guess it doesn’t take much to push 550W of power anyway! There’s quite a bit of space between the few components through, so airflow and cooling will hopefully be pretty good.


The AC line filtering stage is looking decent enough, but some of the soldering looks a bit scruffy.


It’s quite hard to see the main output capacitors here due to the mess of cables that is required for those hard-wired connectors, but there’s a mixture of Samxon, Nippon, Taicon and Rubycon thrown into the mix, certainly a better selection than I was expecting.


The main bulk capacitor is a Samxon made part, rated for 220uf, 450v and 105c.


A small PCB at the front provides some of the lower voltage cables and there’s a few smaller caps, as well as a few other small PCBs with coils on them. I’ve not seen this design before, but it seems practical from a cooling point of view.


The fan is nothing fancy, just a 2200RPM 120mm fan, which is speed controlled by the PSU.



Test Procedure

At eTeknix we take the power supply testing procedure very seriously and have invested a lot of resources into acquiring the appropriate testing equipment. For all power supply reviews we test the power supplies with dedicated power supply testing equipment. This means we are able to get the most accurate results from our testing as opposed to using software benchmarks (such as OCCT) or multi-meter readouts which are broadly inaccurate.


Our test machinery is as follows:

  • Sunmoon SM-5500ATE Active Load Tester (1200W rated)
  • Stingray DS1M12 USB Oscilloscope
  • Voltcraft DT-10L laser tachometer

The eTeknix test procedure involves:

  • Testing each power supply at 20/40/60/80/100% load (with balanced load across all rails) and measuring PFC (power factor correction), efficiency (actual power divided by power “pulled at the wall”) and voltage regulation (deviance from expected voltages of 3.3/5/12 on the main rails).
  • Measuring ripple with an oscilloscope at 20/40/60/80/100% load.
  • Measuring fan speed after a stabilisation period of five minutes at each load scenario using the Voltcraft DT-10L laser tachometer and a reflective strip on the fan.
  • Testing each power supply’s OPP (Over Power Protection) mechanism and seeing how many watts each power supply can deliver before shutting down

Other things to consider are that

  • We recognise that a single yellow 12 volt cable can provide only 6 Amps before overheating (which corrupts voltage regulation and efficiency) and so we used an adequate number of cables for each power supply to ensure there is not efficiency loss from poor cables selection
  • Our Sunmoon SM-5500ATE power supply tester is not capable of testing more than 300W on each of the 12 volt rails so where a power supply provides more than 300W on a 12 volt rail that power is distributed over multiple 12 volt rails on the load tester. For example a power supply with one 12 volt rail supplying 750 watts would be spread equally over three 12 volt rails on the load tester, a power supply with two 450W 12v rails would be spread over four 12v rails on the load tester, two 225W 12v rails for each of the 12v rails on the unit.
  • We use the same time scale and horizontal millivolt scale on our oscilloscope for all ripple tests, that is a 20ms T/DIV (horizontal) and a 0.02 V/DIV (vertical) meaning the scale is from -80mV to +80mV, ATX spec dictates that the 12v rail must fall within 150mv of ripple and the 3.3/5 within 50mv so that scale allows us to include both 150 and 50mV peaks. (Some older PSU reviews use different scales which were later ditched as the visual representation they give is inadequate, in these reviews written measurements are provided only).
  • Deviance is the terminology used to represent the way voltages diverge from the expected values

Efficiency, PFC and Voltage Regulation

Voltage Regulation

To test voltage regulation we load the power supply to five different load scenarios that give an equal spread of load across every single rail. So that means 20% on all rails, 40% on all rails and so on. We then calculate the average deviance of each rail from its expected voltage.


Voltage regulation is about fairly average, but actually much better than I was expecting for a unit of this price.

Power Efficiency

Power efficiency is measured by calculating actual supplied wattage divided by the wattage drawn at the wall/plug, multiplied by 100 to give a percentage. We then compare that to the particular 80 Plus certification the company claims to see if it meets that. You can see the 80 Plus certifications below, we always test 230v power supplies.



This may be an 80 Plus Bronze rated unit, but it’s mostly within the Silver rating on our tests, only missing out at 50% load by a very small margin. This is great, as you’re mostly getting better than advertised efficiency!

Power Factor Correction

Power Factor Correction is the ratio of the real power flowing to the load, to the apparent power in the circuit. The aim of PFC is to make the load circuitry that is power factor corrected appear purely resistive (apparent power equal to real power). In this case, the voltage and current are in phase and the reactive power consumption is zero. The closer the number to one the better as this allows the most efficient delivery of electrical power (Source – Wikipedia).


PFC is pretty standard, but that in its self is no bad thing.



Noise and Ripple can easily be measured by an oscilloscope. These show how much voltage fluctuation there is on a particular rail. We tested the rail stability of the 3.3 volt, 5 volt and 12 volt rails using an identical time and millivolt scale for all graphs. millivolt ripple is measured by the peak to peak size of the voltage curve.


Sample Ripple Graph

The latest ATX 12 volt version 2.3 specifications state that ripple from peak to peak must be no higher than 50 millivolts for the 3.3 volt and 5 volt rails, while the 12 volt rail is allowed up to 120 millivolts peak to peak to stay within specifications. Millivolt figures are stated to the closest increment of 5 given their variability.

Load (%) 3.3V Ripple 5V Ripple 12V Ripple
20  3.6  4.2  13.2
40  4  4.4  15.4
60  5  4.8  20
80  4.4  5.8  21.4
100  4.8  6.2  25.6

OK, I’m pretty stumped here, these results are very good, not just for a PSU, but for any PSU.

3.3 volt @ 100%


5 volt @ 100%


12 volt @ 100%



Over Power Protection and Max Wattage

Power supplies often quote as having various protection mechanisms such and the most important of these is Over Power Protection. In our testing we crank up the power draw until the power supply either shuts down (meaning the OPP mechanism is present and working) or blows up (meaning it is either not present or not working). We then note the maximum power consumption before the power supply shut down (or blew up).


550W? We managed to crank things up to over 800W before the OPP kicked in. I wouldn’t recommend running the PSU this hard for long periods, but it’s got enough grunt when you need it.


Fan Speed

When testing in a power supply laboratory it is difficult to take fan noise readings as the noise from the Sunmoon test equipment and air conditioning corrupts everything. The next best thing in our circumstances was reading off the fan speed with a tachometer to get an idea for the noise. The ambient temperature during testing held constant at 22 degrees, with 1 degree of variation. Each power supply had a consistent time period of 5 minutes to stabilise between each load scenario. 

In my experience the following general relationships apply between noise levels and fan speeds, though it can vary greatly between the type of fan used.

  • Below 800 RPM – Inaudible/Silent
  • 800 to 1000 RPM – Barely audible
  • 1000 – 1200 RPM – Audible but still quiet
  • 1200 – 1400 RPM – Moderately noisy
  • 1400 – 1800 RPM – Noisy
  • 1800 RPM or higher – Intolerable

There’s no polite way of putting it, the fan Antec have used is rubbish. Sure it keeps the unit running cool, but it’s a little louder than you would want.



Final Thoughts


The price of this PSU is obviously very attractive. If you’re not building a high-end gaming PC, it’s got more than enough power to suit your needs and at under £40, it’s certainly kind to your bank balance. The only downside is that it’s only available for 230v, so you can’t get stock in the US, which is a shame.


When I first saw this power supply, there was a little part of me that wanted to point and laugh. Let’s be honest, it looks a bit rubbish and while I admit that is not out of the ordinary for a budget power supply, it is hard to be particularly excited by products in this price range. Of course, the jokes on me, because after we plugged this unit into our load tester, it’s Antec who are doing the laughing.

The performance on this unit far exceeded my expectations, it’s on par with many of the high-end units we’ve tested in terms of ripple suppression, voltage regulation, PFC and its efficiency is fairly decent (for the price) too. That makes this an absolute bargain for system builders and while its design leaves a lot to be desired, it’s got all the performance in the right places.

The non-braided non-modular cables certainly aren’t attractive, but for a chassis that doesn’t have a window, does that really matter that much? Not really. The only real downside to this unit is the fan noise, it’s certainly audible and I’d be looking for a sound-proofed chassis as the ideal home for this unit. Of course, noise isn’t everyone’s top priority and when you’re looking for price vs performance, you’ll get a damn fine ratio here.


  • Reasonable efficiency
  • Good OPP
  • Excellent ripple suppression
  • Good voltage regulation
  • Very affordable price tag


  • No modular cables
  • Lack of good cable braiding
  • Noisy fan

“This may not be the best looking PSU we’ve ever seen, but when you need an affordable unit for a low-to-mid range system, you’ll have a hard time finding a product that matches the performance on offer here!”

Antec Strictly Power VPF550 Power Supply Review

Antec Strictly Power VPF550 Power Supply Review

Thank you Antec for providing this review sample.

Article Index

  1. Introduction and Packaging
  2. A Closer Look - Exterior
  3. A Closer Look - Interior
  4. Test Procedure
  5. Efficiency, PFC and Voltage Regulation
  6. Ripple Testing
  7. OPP and Max Wattage
  8. Fan Speed
  9. Final Thoughts
  10. View All

Author Bio

Add a Comment

Related Posts