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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.

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Performance, Performance Per Dollar, Noise And Efficiency Ratings

Performance Rating

The following graph shows the total performance rating of the PSU, comparing it to other units we have tested. To be more specific, the L9-CM-600W is shown as 100 percent, and every other unit's performance is shown relative to it.

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Performance is way better than the previous generation, and we can easily say it's good for the standards of this category.

Performance Per Dollar

The following chart may be the most interesting to many of you because it depicts the unit's performance-per-dollar score. We looked up the current price of each PSU on popular online shops and used those prices and all relative performance numbers to calculate the index. If the specific unit wasn't available in the United States, we searched for it in popular European Union shops, converting the listed price to USD (without VAT). Note that all of the numbers in the following graph are normalized by the rated power of each PSU.  

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With an MSRP of $74.90 the L9-CM-600W achieves a high performance per dollar ratio. Compared to the EVGA and Xigmatek offerings that lead in this chart, be quiet!'s PSU offers notably better performance.

Noise Rating

The graph below depicts the cooling fan's average noise over the PSU's operating range, with an ambient temperature between 28 °C and 30 °C (82 °F to 86 °F).

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The L9-CM-600 beats every other offering in this category easily, and it does so without utilizing a semi-passive mode.

Efficiency Rating

The following graph shows the average efficiency of the PSU throughout its entire operating range, with an ambient temperature between 28 °C and 30 °C.

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Compared to Gold- and Platinum-rated units, the L9-CM-600 naturally doesn't stand a chance. However, given its Silver rating, it registers high efficiency overall. Unfortunately, we don't have any other Silver-rated units in our 115V database to compare.

Aris Mpitziopoulos
Aris Mpitziopoulos
Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.
14 Comments Comment from the forums
  • turkey3_scratch
    Really poor unit. For one thing, the crossload performance is poor. Sleeve bearing fan with less reliability. 85C primary capacitor. Once again, another failed 3.3V transient response. Very high inrush current. Also, near worst of all, 140+mv of ripple on the 12V rail in CL2. Just really bad. And CL2 is a realistic scenario these days because those 3.3V and 5V rails don't do much anyway. FSP's soldering is clearly not the same as the nice soldering on their high end units.

    But my largest complaint would have to be voltage regulation (line regulation) under different load scenarios on page 6.
    Reply
  • 4745454b
    85C main cap doesn't bother me that much. It should get airflow from the fan so unless the fan dies (and if it does 105C cap isn't going to help much.) or it gets clogged with dust you should be ok. As for the CL test what do you expect? It's a group regulated design so that's going to happen. It's like buying a super duty truck and then complaining you don't get 30MPG in town. What I find more bothersome is they can't seem to sell you what they claim on the box. If it's not C6 or C7 ready and not a group reg design, why claim so? I wonder if they shipped the wrong unit?
    Reply
  • powernod
    Outstanding review by Aris as always! :)
    If only the PSU itself was outstanding as well:ouch:
    Reply
  • basroil
    Looks like FSP is still mostly a second tier manufacture with those transient response and inrush... does it really hurt that much to put a shuntable thermistor like Seasonic and SuperFlower units have?

    For less than $10 more you can usually find excellent Seasonic and SuperFlower Leadex Gold units, which makes it really hard to say this PSU is anything more than "meh"
    Reply
  • Aris_Mp
    actually I am worried about the bulk cap, because 85C means that it has 4x times lower lifetime than a 105C cap.
    Reply
  • turkey3_scratch
    17839248 said:
    85C main cap doesn't bother me that much. It should get airflow from the fan so unless the fan dies (and if it does 105C cap isn't going to help much.) or it gets clogged with dust you should be ok. As for the CL test what do you expect? It's a group regulated design so that's going to happen. It's like buying a super duty truck and then complaining you don't get 30MPG in town. What I find more bothersome is they can't seem to sell you what they claim on the box. If it's not C6 or C7 ready and not a group reg design, why claim so? I wonder if they shipped the wrong unit?

    Not all group regulated designs are exactly the same way. We see in Seasonic's S12ii series a group regulated design that actually crossloads very well. This seems to be one of the worst on the ladder.

    @Aris: Why is Inactive PWR_OK to DC_LOSS better at a higher value? Once the PWR_OK signal is dropped, wouldn't you want the unit to shut down as quickly as possible, not prolong it?
    Reply
  • powernod
    It was already explained by Aris at his review:
    "The power-good signal lasts longer, so when it drops, the voltage level of the +12V rail is already below 11V."
    When the pwr_ok to DC_loss is higher (*meaning that it has a positive , not negative value) that means that the motherboard will already have been shut-down. (*from what i've understand, at least)
    Reply
  • turkey3_scratch
    Not sure how the motherboard could shut down before the PWR_OK signal is dropped.
    Reply
  • Aris_Mp
    the problem is that in some PSUs, PWR_OK, which informs the mainboard when it should shut down, drops after and not before the rails go our of spec. So once it drops the rails are already too low.

    Normally when AC is removed, the PWR_OK signal should be de-asserted at least 1ms before voltages go out of spec in order not to stress the VRMs of the mainboard and of other components (e.g. VGA, HDD, SSD, etc.).

    The only way to address this issue is to have a circuit on the mainboard checking the input voltages and give the shut down order when these go out of spec. In other words to completely bypass the power_ok signal coming from the PSU. But this will cost money and after all a PSU oughts to follow ATX spec's guidelines.
    Reply
  • turkey3_scratch
    So is "DC_LOSS" considered "voltages out of spec"? I mean, there can still be DC even if voltages are out of spec. It won't be a loss of DC< just an out-of-spec voltage relative to the DC.
    Reply