Be quiet!'s Pure Power L8 700W is a decent mid- to high-end PSU that offers 80Plus Bronze certification and is produced by HEC (OEM). With the price of around US $100 it should not break anyones budget and still offer decent performance.
Presentation
The be quiet! Pure Power L8 700W is packed in a rather simple box,
which is pretty much what you get with most, if not all, PSUs in this price
range. It shows all the usually specifications and features while gives enough
protection to the PSU wrapped inside the bubble-wrap.
The be quiet! Pure Power L8 700W comes bundled with the manual,
standard power cord, a couple of cable tiers in case you want to keep things
tidy in your case as well as four screws to secure it to the
case.
The Pure Power L8 700W uses a black painted case with standard
150x160x86 dimensions and bottom mounted fan placed behind the grill. Since it
is not a modular PSU, all cables come from a single point. The entire unit
weighs 1.93kg. The fan behind the grill is silence-optimized 120mm be quiet! fan
that features durable Rifle-Bearing-Technology and thermal control, offering
best compromise between proper cooling and quiet
performance.
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Photo Gallery
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Delivery and
Specifications
The Pure
Power L8 700W is a non-modular PSU but all cables are sleeved and up to 90cm
long, which allows enough room for cable routing.
Cables
|
Cable |
Length |
1 x ATX 20+4
pin |
50 cm |
1 x EPS/ATX 12V (4+4)
pin |
55 cm |
2x PCI-E 6+2 + 6+2
pin |
50, 50 cm |
1 x 2x SATA + 1x Molex + 1x Floppy |
45, 60, 75, 90 cm |
1 x 3x Molex |
45, 60, 75 cm |
1 x 3x SATA |
45, 60, 75 cm |
Connectivity is decent for the PSU of this class as it
offers four PCI-Express 6+2 power connectors on two separate cables, five SATA
and four Molex connectors, enough for most mid- to higher-end setups. The
cables are the 18 AWG. High-end PSUs normally use better 16AWG or even better
cables. Since is a non-modular PSU there will be no Voltage drops over the
connectors so it should not be considered as a negative
point.
Specifications
|
Voltage |
Current |
Power |
+ 3.3 V |
25 A |
150 Watt |
700 Watt (Total) |
+ 5.0 V |
20 A |
+ 12 V |
53 A |
636 Watt |
- 12 V |
0.3 A |
3.6 Watt |
+ 5 Vsb |
3.0 A |
15 Watt |
As it does not use the single +12V rail design it should be taken
into an account that it actually provides 53Amps on both rails, 35Amps on 12V1
and 30Amps on the second one. Most PSU makers are currently going back to the
single +12V rail design, but we are sure this one does well unless you are
pushing for extreme multi-GPU setups that require much higher-end
PSUs.
The Pure Power L8 700W has been
80Plus Bronze certified. This means, that the efficiency of this PSU should be
above 82% at 20% load, above 85% at 50% load and above 82% at 100% load.
As you can see from the list below, the rest of the features include standard
protections, standard dimensions and a 3-year warranty that is pretty much in
line with most mid-range PSUs from various other manufacturers while high-end
PSUs usually come with 5-year warranty.
- 80Plus Bronze
- OVP, UVP, OCP, SCP, OPP, OTP
- Dimensions (W x H x
D): 150
mm x 86 mm x 160 mm
- 120 millimeter fan
- Warranty: 3
Years
- Price: 100 CHF
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A Look Inside
BeQuiet's Pure Power L8 is based on a HEC OEM design. The
first hint for a high-quality power supply you can get from the transient
filtering stage.
On the primary side you find a rectifier. We can find a PCB housing for the
CM6800. The CM6800 controls the PFC Booster and the Push-Pull converter. This
PSU has a Push-Pull topology using two Mosfets and two Diodes according to the
following primary sided principle:
link
This is an old school standard topology; simple and proven, but it won't achieve
any new efficiency records. Because this topology requires hard switching from
the Mosfets (Switching Mosfets under voltage and current generates losses) this
topology is more and more replaced in the PC PSU market by resonant topologies.
The transformer has two coils on the secondary side, one for 12V and one for 5V.
The 3.3V is generated from the 5V Coil. This is the classic old PSU topology.
The APFC Capacitor with 470uF at 400V and 85°C from Teapo. The PFC Booster uses
a BCY10-600 Hyperfast recovery diode and three FDP18N50 Mosfets. This is quite
normal for the PSU in this price range as SiC Diodes are still quite expensive.
For rectifying the secondary side, Schottky diodes are used. The Output filter
Capacitors are from Teapo. 105°C is written on them.
The OCP, UVP, OVP is done by a WT7527.
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Input/Output Power and
Efficiency
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Result Analysis and
Discussion
Efficiency
115V
|
Load |
Pin(W) |
Pout(W) |
Efficiency |
20 % |
166.54 |
143.03 |
85.88 % |
50 % |
407.5 |
354.85 |
87.08 % |
100 % |
837.4 |
703.82 |
84.05 % |
The 80Plus Bronze certification requirements (82% - 85% - 82%)
are surpassed especially at 20% load. This is the case with most of PSU's that
you can buy today and it mainly originates from the reason of lower losses in
the AC filtering stage and the PFC at 230V AC.
Output Stability
|
Load |
Rail |
Loading(A) |
Output(V) |
20 % |
5V |
1.61 |
5.40 |
3.3V |
1.58 |
3.33 |
12V |
9.91 |
12.06 |
5VSB |
1.00 |
5.08 |
|
50 % |
5V |
2.97 |
5.02 |
3.3V |
2.90 |
3.34 |
12V |
26.57 |
11.98 |
5VSB |
1.54 |
5.03 |
|
100 % |
5V |
5.10 |
5.02 |
3.3V |
5.11 |
3.25 |
12V |
54.02 |
11.86 |
5VSB |
3.00 |
4.97 |
The stability of the output voltages and the outcome
of the crossload tests (results not shown here) are not perfect but still within
the margin and the norms, so they are absolutely satisfactory (especially when
you consider the Topology used in this PSU). Transient loads are a big issue for
this topology. In modern PCs, transient load changes often occur. This can end
in a output voltage that is not within the norm for a short moment. This again
can end up in system instabilities.
Noise |
Load |
|
20 % |
Silent |
50 % |
Audible |
100 % |
Audible |
Noise level results are decent and mostly attributed to be quiet!'s
choice to use its own high-quality thermally controlled 120mm fan with rifle
bearing.
Noise/Ripple |
Voltage |
Noise/Ripple Vpp |
5V |
0.023 |
12V |
0.054 |
-12V |
0.032 |
3.3V |
0.030 |
+5VSB |
0.036 |
The noise values are within the ATX norm. This is a
perfect example for the quality difference between Japanese and non-Japanese
capacitors. The topology used in this PSU is filter friendly and Teapo
capacitors are used in a high amount. However the filter performance is worse
when compared to high end PSUs with Japanese capacitors.
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Conclusion
With the Pure Power L8 700W be quiet! offers a good PSU. The
low Price of just around CHF 100 makes it attractive for low-end and mid-rang
gaming PC's. Another interesting application are home servers. However, we would
recomend a PSU with higher efficiency for this purpose because of the noise, the
heat, the higher electricity usage and the HDD connectors might be an issue.
The fan can be considered as quite silent over a wide power range. When you give
full load to the PSU the fan becomes quite audible.
Be quiet! has combined a nice and decent design with decent level of
manufacturing quality. The parts, which are used to build this unit are quite
good, if you keep their low price in mind. Because of the use of cheap Taiwanese
Teapo capacitors we however do not recommend this device for applications which
require high reliability or an extremely long lifespan.
The
BeQuiet Pure Power L8 700W receives 3 out of 5 stars.
Author: JAVASCRIPT
l.muehle@ocaholic.ch