FSP Epsilon 700w ATX PSU Page: 1

Established in 1993 FSP Group is now known as one of the 10 largest power supply vendors in the world. Known by enthusiasts for manufacturing efficient, stable and quiet units, FSP have won many awards for their previous models of PSU, including the highly regarded 'Blue Storm'.

Since then, FSP have been working on a new range of power supplies named Epsilon which promise to improve on the qualities of its predecessors.

Today I'll be putting the top-end 700w model through its paces to see just how it compares to some of the other units on the market.


No expense has been spared when designing the packaging for the Epsilon series power supplies. Having the most flashy packaging of any PSU I've reviewed to date, it almost seems a shame that most of these units (especially in the UK) won't see their way out on to retailers shelves - but will mostly likely all be sold over the internet.

FSP Epsilon Packaging FSP Epsilon Packaging

FSP Epsilon Packaging FSP Epsilon Packaging

The front and sides of the box don't actually offer much information about the unit and instead concentrate on some flashy space-like graphics. The back of the box offers information about the unit in French and German along with information about the PSU's rail amperage distribution. I was somewhat confused as to why FSP had not included English on the back of the packaging but then came across the hidden compartment at the front of the box.

Secured by a small piece of velcro, the front of the box has a secret flap which opens to reveal the list of features (this time in English), along with a sneak preview of the power supply contained within the box. This is a nice touch, but not something I am sure everyone will see when purchasing the unit.

FSP Epsilon 700w FSP Epsilon 700w

Included in the package are the following items:

- 1x Epsilon Manual
- 4x ATX Screws
- 1x Power Cord
- 1x Epsilon 700w PSU

The power supply its self is held in place by a cardboard frame that sandwiches the unit in the middle of the box. I was disappointed to see that FSP did not place the unit inside a plastic bag, especially when the Epsilon has a high quality painted finish which could be marked by rubbing against the cardboard.

The bundle of cables is held together by a velcro strap which is a nice touch over the normal cable tie method, and could also be re-used to tidy the cables within your case.

FSP Epsilon 700w ATX PSU Page: 2

The following information has been taken directly from FSP's website:

- Supports the latest Intel ATX 2.0 standard. Improve the System Compatibility
- NVIDIA SLI Certified
- Dual Channel PCI-Express
- Supports the latest AMD 64 CPU
- Conforms to WEEE & RoHS Environmental Directives in Europe
- Extremely low noise design, providing consumers with a quiet, good operating environment
- Ultra high power of 700W, providing the super player enough power to ensure a stable system
- Over voltage protection, over current protection, and short circuit protection can protect each part of the computer.
- High quality blue cover coating
- 12 cm light blue fan, enhancing heat dissipation and reaching the minimum noise requirement
- Neat and tight mesh sleeving improves the ventilation.
- Smart Housing easy plugable D-type connector design.
- Honeycombed cooling vents on the case reduce noise and improve the heat dissipation and air flow.

- AC Full Range Input is applicable throughout the world.
- High efficiency and power saving design >85%
- Independent 4 Channel 12V Input design. Provides stable power.
- 0.99 Active PFC. Improves the rate of power utilization.
- 20+4Pin Connector designing compatible to all motherboards in the market.
- 4+4Pin Connector design, complying with the requirement of CPU for ATX or EPS system
- S-ATA Connector design which supplies high transfer S-ATA interface products with stable power
- 2 Channel PCI-E Connector with nVIDIA dual graphic card support
- 8 Pin 12V which supports double CPUs and supplies stable voltage.
- MTBF:100,000 hours


Certainly an extensive list of features provided by the FSP power supply with some impressive efficiency and power output figures too. I'm not quite sure what a "Super Player" is though!

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The first thing that strikes you about the Epsilon 700w is its finish. Painted in metallic blue, the Epsilon sparkles under bright lights and makes me think what a great companion it would be for Coolermaster's Wavemaster Blue case which has a very similar finish. The overall paint job is very good, but does not carry quite the same depth and shine of a cars bodywork.

Probably one of the smallest power supplies I've ever reviewed at 140x150x86mm, (LxWxD) I was surprised that FSP managed to fit such a powerful unit into such a small package. However, despite it's small size the Epsilon did feel quite heavy, buy maybe not as heavy as some of the other small-sized atx units that I've reviewed in the past.

Epsilon 700w Epsilon 700w

The back of the unit sports a honeycomb mesh for allowing air forced into the unit by the 120mm fan to exit out of your case. You may also notice that there is no 110/240v switch present on the back of the unit. This is because the Epsilon, like many other modern PSU's is able to auto-detect the input voltage.

FSP have chosen to cool the unit with a single 120mm fan, which is covered by a silver fan grill. Many manufacturers choose this method of cooling, as it is much quieter and often more effective than using a smaller 80mm fan.

Epsilon 700w Epsilon 700w

The front and sides of the unit are pretty plain, with a couple of small grills to aid in the cooling of some of the components inside.

FSP Epsilon 700w ATX PSU Page: 4

With 700w on tap, you certainly don't want to be short changed when it comes to the number of devices that you can hook up. Most power supplies nowdays offer 2x PCI-E, 6x Molex and 2x SATA as a minimum, but will the Epsilon have more to offer?

FSP Epsilon Cables FSP Epsilon Cables

It's good to see that FSP have decided to sleeve all cables right to the very last connector. Many manufacturers only sleeve some of the cables, or sleeve up to the first connector on every cable. The sleeving job is professional with cable ties holding the sleeving in place, and heat shrink keeping everything neat and tidy.

All connectors are finished in black, with the molex connectors adopting the 'easy grip' design, which should make removal of the connectors from devices easier.

FSP Epsilon ATX FSP Epsilon EPS12v

The ATX connector on the Epsilon is native 24-pin. However, as you can see above, a small block of 4 connectors can be broken off to switch the connector to 20-pin, and thus make it compatible with older motherboards.

This is also true for the 8-Pin EPS12v connector which can be split in half, providing the user with a 4-Pin P4-12v connector.


Molex EPS12v PCIE

With 6 SATA connectors, 6 Molex connectors and 2 Floppy connectors the Epsilon 700w should have enough plugs to power almost any kind of high-end water cooled, RAID system.

FSP Epsilon 700w ATX PSU Page: 5
Looking Inside

As with all power supplies that pass through Overclock3D, I'll be taking a look inside the Epsilon. By doing this I should be able to get a good idea of the overall build quality of the unit and how it is likely to perform in our tests.

FSP Epsilon Internals FSP Epsilon Internals

FSP Epsilon Internals FSP Epsilon Internals

I must admit being rather shocked when I opened up the Epsilon. Knowing that FSP have a reputation for making good power supplies, along with the fact that this unit was rated at 700w, I was expecting to see some beefy components inside. However, I was rather disappointed to see small components, small and poorly designed cooling capabilities and generally a power supply that looked like a generic 400w model.

FSP Epsilon Adjustable Pots

On the upside, one thing I did spot inside the Epsilon 700w was an adjustable potentiometer (pot). Pot's can be used to adjust the voltage output by the rails on the power supply, and can come in handy when voltages droop outside of ATX specifications.

FSP Epsilon Fan

Cooling the Epsilon 700w is a 12cm fan manufactured by Protechnic Electrics. The maximum speed of this fan is 2500rpm at 38.3dB when running at 12v. FSP have also gone to the trouble of including a fan controller which adjusts the speed of the fan based on the PSU load.

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Load Testing

In order for the results from all current and future PSU reviews to remain fair and comparable, Overclock3D uses a custom built Power Supply load stress tester.

The tester is capable of placing loads on the following rails:


+3.3v - 20a Load
+5.0v - 20a Load
+12v1 - 10a Load
+12v2 - 10a Load
+12v3 - 10a Load
+12v4 - 10a Load
(or 10-40a on a single +12v rail)

The results are collected from a Mastech MAS-345 Multimeter which logs its readings via RS232 to a PC.

3.3v Rail +5v Rail

+12v Rail

The results given out by the Epsilon were extremely strange. Rather than the voltage on the rails dropping under load as expected, the voltages on the 3.3v and 12v rails actually increased by quite a worrying amount.

I don't have any real explanation for these results other than the possibility that the Epsilon 700w has some unusual crossloading requirements, or that the power supply has tried to compensate for the load placed on the rails by increasing the voltage (too far).

Either way, an increase in voltage also means a decrease in amperage, which means that the Epsilon may be falling short of its rated output.

Just in case there was an incompatibility between our power supply tester and the Epsilon, we have also tried the unit in our test machine which comprises of the following components: 7900GT, P4 Prescott @ 4.1ghz, 2gb Ram, Laing D5 Pump. The results can be seen below:

Idle Voltage
Load Voltage
+3.3v 3.29
+5v 5.08
+12v1 12.24
+12v2 12.28
+12v3 12.25
+12v4 12.23

When plugged into a high-end PC, the Epsilon gives voltage readings much more like what we'd be expecting. All voltages remained within ATX specification, and despite the +12v rails dipping by around 0.3v, never fell low enough to cause any problems.

Efficiency Testing

Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains against the power (in watts) consumed by the OC3D power supply stress tester.

The results may not be as accurate as those produced by professional testing equipment, but will certainly come in handy when comparing several power supplies against each other.

FSP Efficiency

The Epsilon 700w was placed under a load of 646 watts. This counts for a total of 92% of the power supplies rated output. At this load, the power supply required 723 watts from the mains to produce the 646 watts required by our custom made power supply tester.

Therefore the efficiency of this power supply can be found by a simple equation: (646 / 723) * 100, which works out to be an efficiency rating of 89.3%

With a load of 646w which is very close to the maximum output of this power supply I was pleasantly surprised by the efficiency, which is in line with the figures given by FSP for this unit.


Noise Testing

As mentioned earlier in the review, the Epsilon 700w makes use of a 2500rpm, 38.3dB fan manufactured by Protechnic Electrics, which pushes 80cfm when running at 12v.

This many not seem the kind of fan you'd associate with a quiet running PC. Thankfully FSP limit the speed of the fan based on the PSU load to counteract this.

In idle situations, the power supply is barely audible at 1 metre away. I'd estimate the noise output at idle to be around 20dBA. However under heavy load the Epsilon increases the speed of the fan substantially, making the unit clearly audible for 1 metre away. I would estimate the noise output under load to be around 28-30dBA.

FSP Epsilon 700w ATX PSU Page: 7

The Epsilon 700w is a great looking power supply which breaks away from the plain black power supplies which saturate the market. Despite the unit producing some very strange results on our PSU tester, it managed to easily power our test pc and keep all rails well within ATX specifications.

The good performance coupled with the excellent efficiency of this unit makes it a great choice for those of us who want to power a high end pc whilst also keeping their electricity bills low.

Selling for £105 over at SpecialTech, the Epsilon is priced very competitively against other 700/750w power supplies on the market and is definitely worth checking out for Crossfire and SLI users.

+ Metallic paint finish
+ Good rails when tested on PC
+ Very high efficiency
+ Adjustable pots
+ Plenty of connectors
+ Rail layout suitable for Crossfire/SLI

- Exhibited strange behaviour when placed on our PSU tester
- Could be quieter under heavy load
- Poor internal cooling solution


Thanks to FSP Group for providing this unit for review.

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