be quiet! Pure Power 9 600W PSU Review

be quiet! released the updated Pure Power 9 series that consists of four semi-modular models with capacities ranging from 400W to 700W. Today, we're looking at the 600W implementation to see where it stands in the competitive mainstream market.

be quiet! is a well-known German company with a diverse portfolio of PSU products. As you might guess from its name, be quiet!'s focus is on delivering acoustically-friendly power supplies, and indeed the company's PSUs are some of the quietest you can buy.  During this year's CES, we had the chance to check out the new Pure Power 9 series. These budget-oriented units, manufactured by FSP, feature 80 PLUS Silver efficiency.

The previous Pure Power 8 models were 80 PLUS Bronze-rated, so these new PSUs are certainly an upgrade, boasting a more advanced platform. Those older units utilized a group regulation scheme along with SBRs for rectifying the +12V rail, while the new ones use a synchronous design for +12V regulation and, according to be quiet!, independent regulation of the minor rails. The platform upgrades don't stop there. Solid caps are used for increased reliability and a GTD (gas discharge tube) takes the MOV's place providing over-voltage protection. Frankly, we're not sure that GTDs offer better protection than MOVs; they can withstand higher currents and have lower capacitance, but they're also slow and cause a short circuit once triggered, allowing high currents to flow instantly.

We received the 600W Pure Power 9 (L9-CM-600W) for testing. It sports two +12V rails, and be quiet! claims the PSU is silent even under full load. Its fan has a max speed of 1800 RPM, so obviously the control circuit needs to stay conservative, else it wouldn't facilitate low noise output under high operating temperatures. Without question, the efficiency improvement over last-gen's implementation helps enable this since greater efficiency translates to less heat waste.


The L9-CM-600W is 80 PLUS Silver-rated; we don't review many power supplies with the Silver certification, but we know it's a step up from Bronze, particularly for folks on a budget. You also get the benefit of semi-modular cabling, compatibility with the C6 and C7 sleep states (Haswell-ready) and a maximum operating temperature of 40 °C for full power delivery. Additionally, the PSU includes all of the protection features we'd expect, while our sources indicate that the cooling fan has a sleeve bearing. We couldn't hope for much more in an inexpensive power supply. There is no semi-passive mode unfortunately, but the fan profile isn't aggressive, minimizing noise under normal conditions. Finally, you get a three-year warranty, which is ample in this segment.

Power Specifications

Max. PowerAmps2518322830.3
Total Max. Power (W)600

There are two +12V rails, the first delivering 4A more than the second one. In total, both +12V rails can output 576W, or 96 percent of the unit's maximum. The minor rails also have unequal peak power ratings, as the 3.3V rail delivers more amps than the 5V rail. It seems as though be quiet! wanted to keep the 5V rail's max output low in order to avoid putting huge stress on the +12V rails, since they seem to be regulated together (despite the company's claims that they're independent). Finally, the 5VSB rail is strong enough, with 3A of maximum current output.

Cables And Connectors

Native Cables
DescriptionCable CountConnector Count (Total)
ATX connector 20+4 pin (550mm)11
4+4 pin EPS12V (600mm)1
Modular Cables
6+2 pin PCIe (500mm+150mm)24
SATA (500mm+150mm+150mm)13
SATA (500mm) / Four-pin Molex (+150mm+150mm)12
SATA (500mm+150mm) / Four-pin Molex (+150mm) / FDD (+150mm)12 / 1 / 1

Cable length is ample, as is the distance between connectors. Usually we complain when there's more than 10-11cm between the SATA connectors. However, lately we've noticed cases with SSD mounting locations spread farther apart.

The number of available connectors is more than enough for a budget 600W unit, and the only restriction is a single EPS connector. Then again, we doubt that anyone will put a power supply like this one in a PC with a high-end motherboard requiring two EPS connectors. Finally, all connectors use standard 18-gauge wires.

Power Distribution

Power Distribution
12V1ATX, Peripheral, PCIe 1+2
12V2EPS, PCIe 3+4

Since there are only two +12V rails, some compromises were made. But we don't agree with putting one EPS connector and two PCIe connectors together on the second +12V rail. It would be better if the EPS connector instead shared that rail, which is weaker, with the ATX and peripheral connectors, moving the auxiliary PCIe connectors to the first +12V rail.

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