Kingwin ABT-450MM Power Supply Review
By Gabriel Torres on March 13, 2008
ABT-450MM is one of the most low-end power supplies from Kingwin, targeted to users building a very basic PC. Kingwin promises that this power supply can really deliver its rated power at 50° C. Is that so? Let’s check it out.
As you can see, this power supply uses a big 120 mm fan on its bottom (the power supply is upside down on Figures 1 and 2) and a big mesh on the rear side where traditionally we have an 80 mm fan. We like this design as it provides not only a better airflow but the power supply produces less noise, as the fan can rotate at a lower speed in order to produce the same airflow as an 80 mm fan.
This power supply, however, doesn’t have active PFC. In practical terms this only means that Kingwin can’t sell this product in Europe (you can read more about PFC on our Power Supply Tutorial).
As for efficiency, Kingwin says that this product has a 70% minimum efficiency. Keep in mind that more expensive power supplies have an efficiency of at least 80%. The higher the efficiency the better – an 80% efficiency means that 80% of the power pulled from the power grid will be converted in power on the power supply outputs and only 20% will be wasted. This translates into less consumption from the power grid (as less power needs to be pulled in order to generate the same amount of power on its outputs), meaning lower electricity bills.
This power supply comes with four peripheral power cables: one auxiliary power cable for video cards with 6-pin connector, one cable containing three standard peripheral power connectors, one cable containing two standard peripheral connectors and one floppy disk drive power connector, and one cable containing two SATA power connectors.
The number of connectors is enough for a mainstream user that won’t have more than two SATA devices willing to build an entry-level or mainstream PC with a good video card. However, users with more than two SATA devices (i.e., more than two hard drives) will need to use adapters.
The main motherboard cable uses a 20/24-pin connector, and this power supply has one ATX12V connector, not coming with an EPS12V connector.
On the aesthetic side Kingwin used nylon sleeving only on the main motherboard cable and it comes from inside the power supply housing.
All wires are 18 AWG which is perfect.
This power supply is really manufactured by Super Flower, being a Super Flower SF-450P12N power supply. Interesting enough this model isn’t listed on Super Flower’s website, meaning that Super Flower website is completely outdated (what is more probable, as they are still advertising Computer 2007, which took place in June 2007) or they simply don’t manufacture this power supply anymore, being an old and discontinued product.
We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our Anatomy of Switching Power Supplies tutorial to understand how a power supply works and to compare this power supply to others.
In this page, we will have an overall look, while in the next page we will discuss in details the quality and rating of the components used.
The first impression we had when opening this power supply was that we were in front of a very low-end (“generic”) unit that was put inside a nice housing as the printed circuit board was too small for the size of the housing, as you can see in Figure 3. Let’s see if this was just an impression or if there is some truth about our hunch.
As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.
This power supply has one X capacitor more than needed but it has only one ferrite coil instead of two.
A very interesting feature from this power supply is that its fuse is inside a fireproof rubber protection. So this protection will prevent the spark produced on the minute the fuse is blown from setting the power supply on fire.
In the next page we will have a more detailed discussion about the components used in the Kingwin ABT-450MM.
We were very curious to check what components were chosen for the power section of this power supply and also how they were set together, i.e., the design used. We were willing to see if the components could really deliver the power announced by Kingwin.
This power supply uses one RS605 rectifying bridge in its primary stage, which can deliver up to 6 A (rated at 75° C). This is a satisfactory rating for a 450 W power supply. The reason why is that at 115 V this unit would be able to pull up to 690 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 552 W without burning this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.
On the switching section two 2SC2625 NPN power transistors are used using the half-bridge configuration. This configuration is typical on power supplies without active PFC. As you can see, the transistors used are traditional BJT transistors, not MOSFET parts. They can deliver up to 10 A continuous mode or up to 20 A in pulse mode, which is the case. Both values are given at 25° C.
This power supply uses three Schottky rectifiers on its secondary. Since this unit uses a half-bridge design, the rectifiers use the typical configuration for this topology. Calculating the maximum theoretical current each line can deliver on power supplies using this design is easy: all we have to do is to add the maximum current supported by all diodes connected to the line we are analyzing.
The +12 V output is produced by one S30D60C Schottky rectifier, which can deliver up to 30 A (15 A per internal diode, measured at 80° C), which equals to 360 W. The maximum current this line can really deliver will depend on other components, especially the coil. It is also important to notice that almost all power supplies nowadays use two rectifiers connected in parallel on the +12 V line instead of just one.
The +5 V output is produced by one S60D40C Schottky rectifier, which support up to 60 A (30 A per internal diode, measured at 80° C). So the maximum theoretical power the +5 V output can deliver is of 300 W. Of course the maximum current (and thus power) this line can really deliver will depend on other components, especially the coil, as mentioned before.
The +3.3 V output is produced by another S60D40C Schottky rectifier, which support up to 60 A (30 A per internal diode, measured at 80° C). So the maximum theoretical power the +3.3 V output can deliver is of 198 W. Of course the maximum current (and thus power) this line can really deliver will depend on other components, as mentioned before.
Even though this power supply has a separated rectifier for the +3.3 V output, this rectifier is connected to the same transformer output as the +5 V line, so the maximum current +5 V and +3.3 V can pull together is limited by the transformer.
Here it is crystal clear to us that this power supply uses an obsolete design adapted to meet current market demands – in order words adding SATA power connectors on an old power supply doesn’t mean that the power supply is new! We say that because the +5 V and +3.3 V rectifiers are capable of delivering far more current (and thus power) than the +12 V rectifier. This was the typical scenario with power supplies from SEVEN years ago. Nowadays most power is pulled from the +12 V as the components that pull most of the power – CPU’s and video cards – are connected to the +12 V line.
This power supply thermal sensor is located inside the +12 V coil, as you can see in Figure 11. This sensor is used to control the fan speed according to the power supply internal temperature.
On this power supply the big electrolytic capacitors from the voltage doubler are rated at 85° C, while the electrolytic capacitors from the secondary are rated at 105° C. We couldn’t find out their brands.
This power supply has the following specs:
As you can see this power supply has two virtual rails, the first one rated at 16 A and the second one rated at 17 A. On +12V1 we have all peripheral connectors and the video card auxiliary power cable, while on +12V2 we have the motherboard main cable and the ATX12V cable.
Now let’s see if this power supply can really deliver 450 W of power.
We conducted several tests with this power supply, as described in the article Hardware Secrets Power Supply Test Methodology. All the tests described below were taken with a room temperature between 44.8° C and 50° C. During our tests the power supply temperature was between 50° C and 56° C.
First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching how the reviewed unit behaved under each load. In the table below we list the load patterns we used and the results for each load.
On this review we added a sixth pattern, also pulling 100% of the power supply load (450 W) but with a different current configuration. On test number five we respected the limit posted on the power supply label for the combined +12 V power, which is of 336 W. To respect this limit we had to keep the +12 V currents lower than what we wanted and increase the currents on +5 V and +3.3 V outputs. On test number six we didn’t respect the +12 V combined power limit for this power supply and test it as we wanted, pulling more current from +12 V outputs and less from +5 V and +3.3 V outputs, as this configuration reflects better a typical usage from 2008. Under this scenario we were pulling a total of 384 W from the +12 V outputs.
We also wanted to do these tests because we were criticized for not respecting the +12 V combined limit in our Huntkey Green Star 450 W review, some claiming that maybe this was the reason this Huntkey power supply exploded when we tried to pull 450 W from it. So in this present review we will test the power supply under two different scenarios for its 100% load to see what happens.
+12V2 is the second +12V input of our load tester and on this test it was connected to the power supply ATX12V connector.
If you add all the power listed for each test, you may find a different value than what is posted under “Total” below. Since each output can vary slightly (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. On the “Total” row we are using the real amount of power being delivered, as measured by our load tester.
3 A (36 W)
6.5 A (78 W)
10 A (120 W)
13 A (156 W)
14 A (168 W)
17 A (204 W)
3 A (36 W)
6.5 A (78 W)
9 A (108 W)
12.5 A (150 W)
14 A (168 W)
15 A (180 W)
1 A (5 W)
2 A (10 W)
4 A (20 W)
5 A (25 W)
12 A (60 W)
6 A (30 W)
1 A (3.3 W)
2 A (6.6 W)
4 A (13.2 W)
5 A (16.5 W)
12 A (39.6 W)
6 A (19.8 W)
1 A (5 W)
1 A (5 W)
1 A (5 W)
1.5 A (7.5 W)
2 A (10 W)
2 A (10 W)
0.5 A (6 W)
0.5 A (6 W)
0.5 A (6 W)
0.5 A (6 W)
0.6 A (7.2 W)
0.5 A (6 W)
% Max Load
Ripple and Noise
Obsolete design or not this power supply could truly deliver its labeled power at 50° C. Also, it survived to both our scenarios for the 100% load tests: respecting the maximum combined +12 V wattage stated on the power supply label or not.
Efficiency could be better, but reached a somewhat good result for a power supply based on an old design, capable of surpassing 80% on tests number two (40% load) and three (60%). So if you use this power supply with a simple system pulling between 180 W and 270 W you will have a very good efficiency.
Voltage regulation was also great, within 3% of the nominal voltages, except -12 V output, that was at -11.20 V at test one, -11.55 V at test two, and -12.45 V at tests five and six. Even though according to ATX specification -12 V line can vary 10% of its nominal voltage, we wanted to see a value closer to -12 V here.
The highlight of this power supply was electrical noise and ripple, which was at a very low level. When pulling the full 450 W from this power supply noise at +12V1 was 24.6 mV, at +12V2 was 29.8 mV, at +5 V was 20.8 mV and at +3.3 V was 23.6 mV (values for pattern number five). Just to remember, maximum admissible values are 120 mV for +12 V and 50 mV for +5 V and +3.3 V. This power supply had more ripple than noise (ripple is an oscillation on the output waveform, while noise are the spikes present on that oscillation; all other power supplies we’ve seen to date had more noise than ripple – compare the images below with images obtained on other power supplies to see the difference), but this doesn’t change the fact that it was below maximum specs.
After our basic load tests we tried to pull even more power from Kingwin ABT-450MM keeping it working inside its specs.
Starting from test number six presented in the previous page, we started increasing +12 V currents as much as we could. Configuring our load tester to pull 20 A at each one of its +12 V inputs the power supply wouldn’t turn on, showing us that OPP (Over Power Protection) was in action – which is great.
From there we configured our load tester to pull 20 A from its +12V1 input and 19 A from its +12V2 input and the power supply worked fine for a few minutes, and then silently died. When we disassembled the power supply we tested all major components and none of them were burned – only the fuse. We replaced the fuse (a 7 A slow burn fuse) and the power supply was back to life!
After resurrecting our power supply we configured our tester to pull 19 A from each 12 V input and the power supply worked just fine at a room temperature of 50° C. The complete results from this test can be seen below.
19 A (216 W)
19 A (216 W)
6 A (30 W)
6 A (19.8 W)
3 A (15 W)
0.5 A (6 W)
% Max Load
So basically this power supply over power protection is set a little bit higher from where it should be configured. Anyway, even though this power supply died during our overload tests, we could easily bring it back to life by replacing its fuse. The problem is that replacing a fuse inside a computer power supply is a very complicated process for a regular user, as on this power supply the fuse is soldered directly on the printed circuit board and not installed using a fuse holder.
Noise and ripple was, once again, inside specs, at 29 mV on the +12V1 input from our load tester, 30.4 mV at +12V2 input, 17.6 mV at +5 V and 15.6 mV at +3.3 V. These values are peak-to-peak voltages and can be seen on the figures below.
We tested over current protection (OCP) by leaving only the main motherboard connector installed on our load tester and configuring it to pull 28 A from the power supply. Since the power supply worked just fine, we can assume that this power supply doesn’t have an OCP circuit or it is configured at a value higher than 28 A.
Short-circuit protection was tested and was working just fine.
This power supply fan runs very slowly and produces almost no noise. This power supply was running 6-7 degrees Celsius above room temperature, which is fine but a little bit higher than other good power supplies we reviewed, where they typically stayed between 2° C and 5° C above room temperature.
Kingwin ABT-450MM power supply specs include:
* Researched at NewEgg.com on the day we published this review.
Technically speaking, this power supply uses a very old project, with the +5 V and +3.3 V rectifiers having a far higher current limit than the +12 V rectifier, which was a typical configuration from years ago, where the PC pulled the most of its power from +5 V and +3.3 V and not from +12 V as it is today, plus the half-bridge topology, which is typical on power supplies without active PFC (power supplies with this circuit uses a more modern topology, two-transistor foward).
But we were really impressed by the results we could achieve. This power supply could not only deliver its labeled 450 W at 50° C, but we could pull up to 515 W from it, also with a room temperature of 50° C. This is an outstanding performance.
We were also impressed by the low level of ripple and noise produced by this power supply.
Good news is that this power supply has its overload protection up and running and it didn’t explode during our tests. However, during one of our overload tests the fuse blew, so we can say that overload protection circuit (OPP) should be configured with a value a little bit lower to prevent this from happening. The good thing was that after replacing the fuse the power supply continued working just fine. Fuse is a protection, but the problem is most users aren’t able to replace the fuse from this power supply as it is soldered to the printed circuit board.
Efficiency wasn’t bad for a power supply with such old project. With the power supply working between 40% and 60% of its labeled power efficiency was above 80%, dropping below that under other load patterns. So if you buy this power supply to install it on a system that will pull between 180 W and 270 W it will have a decent efficiency. You can calculate how much power your system will pull by using this excellent on-line power supply calculator.
On the down side we have the number of available connectors, only five peripheral connectors and only two SATA connectors. If you have more than two SATA devices (e.g., two hard drives) then you will need to use an adapter to convert the standard peripheral power plugs into SATA power plugs. It also comes with only one video card connector and it doesn’t have an EPS12V connector, but for the audience this power supply is targeted – users building a basic PC –, this isn’t a problem.
Costing between USD 35 and USD 40 this is certainly a good option for users on a tight budget building a basic PC with not so many peripherals. And keep in mind that you are paying for a 450 W product and bringing home a 500 W power supply.
Certainly this is not the best 450 W power supply around, but it does a decent job for its price range, and that is why we are giving it our Bronze Award seal.