[nextpage title=”Introduction”]
BFG, the traditional video card manufacturer, has recently entered into the Power Supply business. Their 800 W model has two 80 mm fans to cool down the unit and the PC and two (BFGR800WPSU) or four (BFGR800WPSULE) PCI Express auxiliary connectors, to feed two (BFGR800WPSU) or four (BFGR800WPSULE) video cards under SLI or CrossFire configuration. Let’s take an in-depth look inside this power supply and see if it can really deliver its labeled 800 W.
Currently there are two versions of this power supply. The first version, called BFGR800WPSU, has two power cables for video cards and right after it was launched BFG discovered that these cables were too short. So they launched a second version, called BFGR800WPSULE, with four video card power cables, increasing the length on the two extra cables. The box of the product is absolutely the same with the newer version having a sticker saying "NEW Limited Edition – Features Four PCI Express Power Connectors" on it.
Figure 1: BFG 800 W power supply.
Figure 2: BFG 800 W power supply.
As you can see on Figures 1 and 2 this unit doesn’t have any fancy feature like modular cabling system and its visual is very plain. As we mentioned, it has two 80 mm fans, one at the rear side of the unit and the other at the front side of the unit.
It features active PFC, a standard feature for high-end power supplies (you can see this not only by the sticker in Figure 1 but by the absence of a 110/220 V switch, which isn’t present on power supplies with this feature). This feature provides a better usage of the power grid and allows this power supply to be comply with the European law, making BFG able to sell it in that continent (you can read more about PFC on our Power Supply Tutorial).
BFG, however, doesn’t mention anything about efficiency on the product box or on their website. This is definitely something we should check our closer during our tests.
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 – compare to less than 70% on regular power supplies.
This power supply comes with seven (BFGR800WPSU) or nine (BFGR800WPSULE) peripheral power cables: two (BFGR800WPSU) or four (BFGR800WPSULE) auxiliary power cables for video cards with 6-pin connectors, two cables containing three standard peripheral power connectors and one floppy disk drive power connector each, one cable containing two standard peripheral connectors and two cables containing three SATA power connectors each.
The first version of this power supply has the problem of having only two power cables for video cards. If you need four cables, choose the "Limited Edition" model, which has all four connectors. Notice that the first version is cheaper than the second because of this.
As we explained, after releasing this power supply BFG found out that the video card power cables weren’t long enough for some SLI and CrossFire configurations, so they released an extension plug for them costing USD 5 each (or free of charge if you call their support department and provide the serial number of your power supply). This extension plug uses a 6/8-pin connector, so if you have a video card that requires an 8-pin connector you will need to buy this extension as well.
Figure 3: Extension plugs for the BFG 800 W.
On the second "Limited Edition" version BFG kept these two cables (approximately 16" or 40 cm in length and using light blue connectors) and added two more PCI Express cables measuring approximately 20" or 51 cm in length each (with dark blue connectors).
On the aesthetic side the plastic sleeving used by the cables come from inside the power supply (see Figure 2), which is great.
This unit comes with five Velcro and two nylon cable holders to help you organize the cables inside your computer, helping the PC internal airflow.
Figure 4: Cable holders that come with the product.
The wires on the main motherboard cable are 16 AWG, which is great, but the wires used on all other connectors are 18 AWG, which is thinner. It would be interesting to see all wires 16 AWG. On the "Limited Edition" model the two additional video card power cables (with dark blue connectors) use only two thicker 14 AWG wires instead of six 18 AWG, being divided into six 18 AWG wires on the connector.
This power supply is really manufactured by Topower.
[nextpage title=”A Look Inside The BFG 800 W”]
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.
We can point out several differences between this power supply and a low-end (a.k.a. “generic”) one: the construction quality of the printed circuit board (PCB); the use of more components on the transient filtering stage; the active PFC circuitry; the power rating of all components; the design; etcetera.
Figure 5: Overall look.
Figure 6: Overall look.
Figure 7: Overall look.
[nextpage title=”Transient Filtering Stage”]
As we mentioned on other articles, 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 than that, usually removing the MOV, which is essential for cutting spikes coming from the power grid, and the first coil.
On this section this power supply is flawless, as it has more components than the necessary – two extra X capacitors, two extra Y capacitors and one extra coil.
Figure 8: Transient filtering stage.
On almost all power supplies we’ve seen lately some components from the filtering stage are attached to the power cord connector, which isn’t the case of this power supply.
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 BFG 800 W.
[nextpage title=”Primary Analysis”]
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 BFG.
From all the specs provided on the databook of each component, we are more interested on the maximum continuous current parameter, given in ampères or amps for short. To find the maximum theoretical power capacity of the component in watts we need just to use the formula P = V x I, where P is power in watts, V is the voltage in volts and I is the current in ampères.
We also need to know under which temperature the component manufacturer measured the component maximum current (this piece of information is also found on the component databook). The higher the temperature, the lower current semiconductors can deliver. Currents given at temperatures lower than 50° C are no good, as temperatures below that don’t reflect the power supply real working conditions.
Keep in mind that this doesn’t mean that the power supply will deliver the maximum current rated for each component as the maximum power the power supply can deliver depends on other components used – like the transformer, coils, the PCB layout, the wire gauge and even the width of the printed circuit board traces – not only on the specs of the main components we are going to analyze.
For a better understanding of what we are talking here, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses two GBU606 rectifying bridges in its primary stage, which can deliver up to 6 A (rated at 100° C) each so the total current the rectifying section of this power supply can handle is of 12 A. This is more than adequate rating for a 800 W power supply. The reason why is that at 115 V this unit would be able to pull up to 1,380 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,104 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.
The active PFC circuit from this power supply uses three power MOSFET transistors instead of just two like the vast majority of power supplies on the market (the only other power supplies we’ve see using three transistors instead of two were OCZ StealthXStream 600 W and Zalman ZM600-HP). The transistors used are 20N60C3, the same one used by several other power supplies we reviewed, which are capable of delivering up to 300 A @ 25° C each in pulse mode (which is the case) or 45 A @ 25° C or 20 A @ 110° C in continuous mode.
Figure 9: One of the rectifying bridges and active PFC transistors.
On the switching section other two 20N60C3 power MOSFET transistors in two-transistor forward configuration are used. Even though these transistors have the same specs from the ones used on the active PFC circuit, they use a bigger packaging (TO-247 vs. TO-220), improving heat dissipation.
Figure 10: Active PFC diode, switching transistors and the second rectifying bridge.
This power supply uses a CM6800 integrated circuit in its primary, which is a very popular active PFC and PWM controller combo. It is located on a small printed circuit board shown in Figure 11.
Figure 11: Active PFC and PWM combo controller.
[nextpage title=”Secondary Analysis”]
This power supply uses eight Schottky rectifiers on its secondary.
The +12 V output is produced by four 48CTQ060 Schottky rectifiers connected in parallel, which can deliver up to 40 A each (20 A per internal diode, measured at 111° C). The maximum theoretical current the +12 V line can deliver is given by the formula I / (1 – D), where D is the duty cycle used and I is the maximum current supported by the rectifying diode (which in this case is made by four 20 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 114 A or 1,371 W for the +12 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used. As you can see this stage is highly overspec’ed.
The +5 V output is produced by two STPS30L45CT Schottky rectifiers connected in parallel, which support up to 30 A (15 A per internal diode, measured at 135° C) each. The maximum theoretical current the +5 V line can deliver is given by the formula I / (1 – D), where D is the duty cycle used and I is the maximum current supported by the rectifying diode (which in this case is made by two 15 A diodes in parallel). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 43 A or 214 W for the +5 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.
The +3.3 V output is produced by two other STPS30L45CT Schottky rectifiers connected in parallel, which support up to 30 A (15 A per internal diode, measured at 135° C)
each. Following the same math, this output would be able to deliver up to 43 A or 141 W, in theory.
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.
Figure 12: Four of the eight Schottky rectifiers used on the secondary. The diode on the left is used by the +5VSB output.
Figure 13: The other four rectifiers.
On this power supply the thermal sensor is installed inside the +12 V coil. The purpose of this sensor is to control the fan speed according to the power supply internal temperature.
On this power supply the active PFC capacitor is rated at 85° C, while the electrolytic capacitors from the secondary are rated at 105° C and are manufactured by CapXon, a Taiwanese company.
[nextpage title=”Power Distribution”]
In Figure 14, you can see BFG 800 W label stating all its power specs. BFG doesn’t say under which temperature their power supply is labeled (but don’t worry, we will test this).
Figure 14: Power supply label.
As you can see this power supply has four virtual rails, each one rated at 20 A. These rails are distributed as following:
- +12V1: Main motherboard cable.
- +12V2: EPS12V and ATX12V cables.
- +12V3: One of the SATA cables, one of the PCI Express (video card) cables and one of the peripheral cables containing three connectors.
- +12V4: The other SATA cable, the other PCI Express (video card) cable, the other peripheral cable containing three connectors and the peripheral cable containing two connectors.
On the "Limited Edition" model the two extra PCI Express auxiliary cables are connected in parallel with the two existing video card cables, therefore on this model we have two video card power cables connected to the +12V3 rail (one light blue and the other dark blue) and another two video card power cables connected to the +12V4 rail (one light blue and the other dark blue).
We think that BFG made a terrific job on the rail balancing. Several power supplies connect the EPS12V and ATX12V cables on different rails, which doesn’t make sense as they aren’t used at the same time (maybe there is one or two extremely high-end motherboards that do, but they are the exception, not the rule).
The only problem we see is that there is no way to identify which of the SATA, PCI Express (video card) and peripheral cables are connected to which rail without opening the power supply, as there is nothing identifying them externally! This is really a shame. BFG should have labeled these cables as “1” and “2” so you could know which cables are sharing which rail.
[nextpage title=”Load Tests”]
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 wit a room temperature between 46° and 50° C. During our tests the power supply temperature was between 49° and 52° 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.
+12V2 is the second +12V input of our load tester and on this test it was connected to the power supply EPS12V connector.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12V1 | 5.5 A (66 W) | 12 A (144 W) | 18 A (216 W) | 25 A (300 W) | 30 A (360 W) |
| +12V2 | 5.5 A (66 W) | 11 A (132 W) | 17 A (204 W) | 22 A (264 W) | 29 A (348 W) |
| +5V | 2 A (10 W) | 4 A (20 W) | 6 A (30 W) | 8 A (40 W) | 8 A (40 W) |
| +3.3 V | 2 A (6.6 W) | 4 A (13.2 W) | 6 A (19.8 W) | 8 A (26.4 W) | 8 A (26.4 W) |
| +5VSB | 1 A (5 W) | 1 A (5 W) | 1.5 A (7.5 W) | 2 A (10 W) | 3 A (15 W) |
| -12 V | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.5 A (6 W) | 0.8 A (9.6 W) |
| Total | 160 W | 320 W | 483 W | 646 W | 799 W |
| % Max Load | 19.9% | 40.0% | 60.0% | 80.8% | 100.0% |
| Result | Pass | Pass | Pass | Pass | Pass |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 188 W | 375 W | 580 W | 801 W | 1,038 W |
| Efficiency | 85.1% | 85.3% | 83.3% | 80.6% | 77.0% |
We were satisfied with these results. BFG 800 W could deliver its labeled power under between 45° and 50° C and could maintain a high efficiency on tests 1 (20% load), 2 (40% load) and 3 (60% load). On test 4 (80% load) efficiency dropped to 80.6% but that is still good. The problem was when delivering its full 800 W, when efficiency dropped below 80% to 77%. This is why BFG isn’t advertising this power supply’s efficiency.
We were really impressed by the very low level of electrical noise produced by this power supply on its +12 V output, the lowest we’ve seen to date. On test 1 (20% load) we’ve seen only 15 mV of noise at the +12 V line, increasing to the 20 mV range for tests 2, 3 and 4 and reaching a maximum of 36.2 mV with the power delivering its full power. This is far below the 120 mV limit and we are talking about a power supply with a noise level 3.5 times below the limit, which is really outstanding. On the other hand with the power supply delivering 800 W noise level at +5 V line was of 27 mV and at +3.3 V line was of 25.4 mV. Even though these numbers are below the 50 mV limit for these lines, we expected something lower here, around 15 to 20 mV, especially when we have such a good filtering on the +12 V line. All these numbers are peak-to-peak figures. Below we show the noise level we found on the power supply outputs while the unit was operating at its full load (test number five).
Figure 15: Noise level at +12V1 input of the load tester.
Figure 16: Noise level at +12V2 input of the load tester.
Figure 17: Noise level at +5V input of the load tester.
Figure 18: Noise level at +3.3V input of the load tester.
The stability of the outputs was also great. All voltages were within 3% their nominal voltage, except the +5VSB on test 1, which was delivering 5.19 V (3.8% above the nominal voltage) and the +5 V on test 1, 2 and 5, which was delivering 5.17 V (3.4% above the nominal voltage). These values are great as they are below the 5% maximum tolerance (on our methodology we use 3% as our goal, which is a tighter figure).
[nextpage title=”Overload Tests”]
After these tests we tried to pull even more power from BFG 800 W. Below you can see the maximum amount of power we could extract from this unit keeping it working with its voltages and electrical noise level within the proper working range. During this test room temperature was of 51° C and the power supply was working at 57° C.
| Input | Maximum |
| +12V1 | 33 A (396 W) |
| +12V2 | 30 A (360 W) |
| +5V | 9 A (45 W) |
| +3.3 V | 9 A (29.7 W) |
| +5VSB | 3 A (15 W) |
| -12 V | 0.8 A (9.6 W) |
| Total | 855 W |
| % Max Load | 106.9% |
| AC Power | 1,137 W |
| Efficiency | 75.2% |
Here noise level increased to 44.4 mV at +12 V, 31.4 mV at +5 V and 25.2 mV at +3.3 V, which are great numbers.
The problem, however, is that after less than five minutes working under this configuration the power supply completely died. We tried to turn it on with 20% load and nothing. We waited until its temperature dropped to below 30° C and, again, nothing. We killed our BFG 800 W!
After opening the unit we found out that we burned one of the four +12 V rectifiers. Which is strange, as we were pulling 63 A from the 12 V outputs and the theoretical combined limit of the rectifiers was of 160 A, as we saw when we analyzed the secondary of this power supply. Should we categorize this as a bad luck of getting a defective unit?
Anyway, this is bad. A power supply isn’t supposed to burn only because you overloaded it. In fact this is exactly why the over power protection (OPP) exists, to prevent things like this from happening.
Another hypothesis is that this rectifier burned because it was overheated (during this test the power supply housing was at 57° C, so imagine the secondary heatsink temperature) and the power supply over temperature protection (OTP) didn’t kick in. This makes sense as the temperature sensor of this power supply isn’t installed on the secondary heatsink, but inside the +12V coil.
Over current protection (OCP) seemed to be configured at 30 A – even though the power supply label says that the limit for each rail is of 20 A –, as we couldn’t pull more than 30 A from +12V2 input, where we had one of the rails (+12V2) connected alone.
During our tests we could see the speed of the power supply fans changing as the power supply temperature increased. Below 30° C they spin slowly, making almost no noise, and after this temperature they start increasing their speed, also increase noise level.
[nextpage title=”Main Specifications”]
BFG 800 W power supply specs include:
- ATX12V 2.2
- Nominal labeled power: 800 W.
- Measured maximum power: 850 W at 50° C (see text).
- Labeled efficiency: N/A
- Measured efficiency: Between 77% and 85.3% at 115 V.
- Active PFC: Yes.
- Motherboard Connectors: One 20/24-pin connector, one ATX12V connector and one EPS12V connector.
- Peripheral Connectors: two (BFG800WPSU) or four (BFG800WPSULE) video card power cables, two cables containing three standard peripheral power connectors and one floppy disk drive power connector each, one cable containing two standard peripheral power connectors and two cables containing three SATA power connectors each.
- Protections: N/A.
- Warranty: Lifetime for US customers and 10 years for European customers.
- More Information: https://www.bfgtech.com
- Real manufacturer: Topower
- Average price in the US*: USB 100.00 (BFGR800WPSU) or USD 130.00 (BFGR800WPSULE)
* Researched at Tigerdirect.com on the day we published this review.
[nextpage title=”Conclusions”]
This power supply from BFG can truly deliver 800 W of power at 50° C, which is outstanding. The level of electrical noise on the +12 V outputs is the lowest we’ve seen to date (36 mV against 90 mV on Corsair TX750W, for example), but on the other hand we’d like to see a lower noise level on the +5 V and +3.3 V outputs, even though they were within specs.
In the USA the "Limited Edition" version can be found for only USD 130, while the first version that has only two cables can be bought at Tigerdirect.com for only USD 100.00 (just as a reference Corsair TX750W costs around USD 180) – and a lifetime warranty in the US (or 10 years in Europe) make this a very attractive product, being a power supply with one of the best cost/benefit ratios in the world today.
Once again we’d like to remember that the very first version, BFGR800WPSU, doesn’t offer four video card power cables, what doesn’t make sense for an 800 W product. On this model the cables may be too short depending on the video cards you have (BFG provides an extension that solves these two problems if you call their support department and provide the power supply serial number). BFGR800WPSULE ("Limited Edition") model corrects this problem adding two extra longer cables. Anyway, both products use 6-pin connectors, not 6/8. Competing products may also offer more SATA and peripheral connectors.
Another problem with this unit is its efficiency at full load, below 80% – even though it reached an efficiency between 80% and 85% during lighter loads.
But what for us was the real bummer was the fact that we burned this power supply when we overloaded it (probably due to an overheating on the secondary heatsink). Some can argue that if a power supply works within the manufacturer’s proposed specs it is a good product, but we don’t agree. We think this unit needed to shut down instead of burning. We know that you can replace this power supply for free for the rest of your life (if you live in the US), but nobody likes to wait some days to get his (or her) computer back working. Anyway, we need to give BFG the benefit of doubt and maybe we got the bad luck of getting a defective unit.
Because of the flaws described above we can’t give it our “Golden Award” seal, but because of its very low price for an 800 W product and its insane warranty, we are awarding it with our “Silver Award” seal.