be quiet! Straight Power 11 650W Platinum Power Supply Review

be quiet! Straight Power 11
(Image: © be quiet!)

Tom's Hardware Verdict

The be quiet! Straight Power 11 Platinum with 650W max power is silent and uses quality parts. These features are not enough, though, to allow it to meet the competition effectively, and its price in the US market is stiff.


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    Full power at 47 degrees Celsius

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    Silent operation

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    Quality components

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    Long hold-up time

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    Fully modular

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    Compatible with the alternative sleep mode

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    Adequate distance between the peripheral connectors


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    The protection features are not configured correctly

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    Not so high overall performance

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    One of the EPS cables has two of these connectors

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    High Vampire Power

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    Lower than 70% efficiency with 2% load

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    Mediocre soldering quality

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The be quiet! Straight Power 11 Platinum with 650W capacity (E11-PT-650) offers dead silent operation and has compact dimensions. Are those two features enough, though, to match opponents like the formidable Corsair RM650x and the Seasonic Focus Plus Platinum 650W? Although the RM650x has a lower efficiency rating in the 80 PLUS scheme, still its overall performance is notably higher than the E11-PT-650, and the same goes, of course, for the Seasonic model. Given the high prices of all be quiet! products in the US, there is no reason to select the E11-PT-650 over the two products mentioned above. It's a solid choice but not one of the best power supplies.

The new Straight Power 11 Platinum line from be quiet! is made by FSP, like the previous one, and uses a new platform featuring a full-bridge topology. The Straight Power 11 Platinum models start from 550W and go up to 1200W, for users that need more power. The older, Gold, line starts from 450W and reaches up to 1000W. Besides the different capacities, the number of EPS connectors has also been increased in the new models. Only the E11-PT-550 comes with a single EPS, with all the other models featuring two, except the 650W and 750W units, which have three EPS connectors! There is no need, of course, for three EPS in any power supply. The E11-PT-750W and 650W might come with three EPS connectors, but only two of them can be used at the same time, with both of them hosted on the same cable. You can read more on this below, in the cable and connectors description.

The E11-PT-650W is the second smallest member of the family. Besides a fully modular cable design, it also features a Silent Wings 3 fan, which is driven by a relaxed fan speed profile. All be quiet! products are known for their quiet operation, and this PSU is not an exception. Finally, for the internals, FSP used high-quality components, and this is why the price of this product is increased, especially in the US market.


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Manufacturer (OEM)


Max. DC Output



80 PLUS Platinum, *ETA-A (88-91%)


*LAMBDA-A+ (15-20 dB[A])


✓ (Fully)

Intel C6/C7 Power State Support

Operating Temperature (Continuous Full Load)

0 - 40°C

Over Voltage Protection

Under Voltage Protection

Over Power Protection

Over Current (+12V) Protection

Over Temperature Protection

Short Circuit Protection

Surge Protection

Inrush Current Protection

Fan Failure Protection

No Load Operation


135mm Fluid Dynamic Bearing Fan (BQSIW3-13525-HF)

Semi-Passive Operation

Dimensions (W x H x D)

150 x 85 x 155mm


1.65 kg (3.64 lb)

Form Factor

ATX12V v2.4, EPS 2.92


5 Years

Power Specifications

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Max. PowerAmps2424181822223
Total Max. Power (W)650

Power Distribution

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12V1ATX, Peripheral

The power distribution is good, because the EPS and PCIe connectors are powered by different rails.

Cables & Connectors

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DescriptionCable CountConnector Count (Total)GaugeIn Cable Capacitors
ATX connector 20+4 pin (600mm)1116-22AWGNo
4+4 pin EPS12V (700mm)1116AWGNo
4+4 pin EPS12V (700mm) / 8 pin EPS12V (700mm)1218AWGNo
2x 6+2 pin PCIe (600mm) 2418AWGNo
SATA (550mm+150mm+150mm+150mm)1418AWGNo
SATA (550mm+150mm+150mm) / 4-pin Molex (+150mm)13 / 118AWGNo
SATA (550mm+150mm) / 4-pin Molex (+150mm+150mm)12 / 218AWGNo
FDD Adapter (150mm)1122AWGNo
AC Power Cord (1360mm) - C13 coupler1118AWG-

Since the PSU only has one EPS socket, and be quiet! wanted to equip it with a pair of those connectors, it comes with two different EPS cables. The first hosts a single connector while the second has two of these connectors. The problem is that you cannot fully exploit two of those connectors with the same cable, especially if you use 18AWG gauges. Each EPS can draw up to 336W, so a pair of them can easily damage the corresponding socket on the modular panel, along with the connector on the PSU side. Nevertheless, be quiet! chose to go on with this weird cable because the PSU has four +12V rails, so with the proper OCP setting on the corresponding rail, it is safe to use a pair of EPS on the same cable. 

All cables are long enough, and the number of peripheral connectors is satisfactory. Finally, the distance between the SATA and the 4-pin Molex is adequate, at 150mm. 

Component Analysis

We strongly encourage you to have a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss.

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General Data-
Manufacturer (OEM)FSP
PCB TypeDouble Sided
Primary Side-
Transient Filter5x Y caps, 2x X caps, 2x CM chokes, 1x MOV
Inrush ProtectionNTC Thermistor (SCK-056) & Relay
Bridge Rectifier(s)1x
APFC MOSFETs2x ROHM R6030KNX (600V, 30A, 0.13Ohm)
APFC Boost Diode1x STMicroelectronics STPSC6H065 (650V, 6A @ 110°C)
Hold-up Cap(s)1x Nippon Chemi-Con (420V, 270uF, 2,000h @ 105°C, KMQ) & 1x Nippon Chemi-Con (450V, 180uF, 2,000h @ 105°C, KMR)
Main Switchers4x ROHM R6020KNX (600V, 20A, 0.196Ohm)

IC Driver

2x Silicon Labs Si8233BD

APFC ControllerChampion CM6500UNX
Resonant ControllerChampion CM6901X
TopologyPrimary side: Full-Bridge & LLC converter
Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side-
+12V MOSFETs4x Infineon BSC010N04LS (40V, 100A @ 100°C, 1mOhm)
5V & 3.3VDC-DC Converters: 8x Advanced Power AP3R303GMT (30V, 25A @ 70°C, 3.3mOhm)
PWM Controllers: 2x ANPEC APW7164
Filtering CapacitorsElectrolytic: 4x Nippon Chemi-Con (4-10,000h @ 105°C, KY), 2x Nippon Chemi-Con (5-6,000h @ 105°C, KZH), 5x Rubycon (3-6,000h @ 105°C, YXG)
Polymer: 4x FPCAP, 18x United Chemi-Con
Supervisor ICWeltrend WT7527 (OCP, OVP, UVP, SCP, PG)
Fan Modelbe quite! BQ SIW3-13525-HF (135mm, 12V, 0.56A, Fluid Dynamic Bearing Fan)
5VSB Circuit-
Rectifier1x CET CEF03N8 FET (800V, 2A @ 100°C, 4.8Ohm)
Standby PWM ControllerLeadtrend LD7750R

As we also state in the E11-PT-550W review, this line uses a brand new FSP platform, which we will also see in the Hydro PTM Pro line. The design is modern with a full-bridge topology on the primary side, which is supported by an LLC resonant converter, for increased efficiency. On the secondary side, several FETs regulate the +12V rails, and a pair of VRMs handle the minor rails. 

The parts are of good quality, especially the bulk caps and the filtering caps on the secondary side. 

The transient filter has all necessary parts, to effectively deal with EMI emissions, both incoming and outcoming. 

(Image credit: Tom's Hardware)

There is one bridge rectifier, while most PSUs in this price range and capacity use two, for lower energy losses. 

The APFC converter uses two ROHM FETs and a single boost diode, provided by STMicroelectronics. There are two bulk caps, with their combined capacity reaching 450uF, which is low for a 650W power supply. But the hold-up time also has to do with the design and the APFC controller's tuning. 

The four primary switching FETs are configured in a full-bridge topology, with an LLC resonant converter also used for higher efficiency. 

The +12V FETs are installed on the rear side of the PCB, and the soldering quality in this area doesn't look good. 

The filtering caps are of high quality. Besides electrolytic caps, a large number of polymers also handle ripple filtering. 

(Image credit: Tom's Hardware)

The supervisor IC is a Weltrend WT7527, which supports all protection features but OTP (Over Temperature Protection). The latter protection is implemented through another circuit, which most likely uses the WT7527, to shut down the PSU.

The primary rectifiers in the 5VSB circuit is a CET CEF03N8 FET, and the standby PWM controller is a Leadtrend LD7750R IC.

Ten polymer caps are on the face of the modular panel, for an extra ripple filter layer. 

The soldering quality is mediocre. In several areas the soldering joints are sloppy.