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be quiet! Straightpower 450W & 600W

You’ll be happy with either model, just think of what you’ll run. For Crossfire / SLI however I’d rather recommend the 600W model as it’s a more of a future proof investment. The 450W version supports dual graphics, but it might “squeak” if you throw a whole lot more at it. Straightpower PSUs are efficient and quiet, but with drawbacks; both produce high voltages for 12v rails.


I’d like to thank Listan for making this review possible.

The company behind be quiet! products is Listan (Revoltec is also their brand). They are a leading hardware distributer in Europe with massive amount of resellers all over the world. So what about be quiet! ? It’s a recognizable brand to a wide crowd, especially system integrators and enthusiasts looking for grade A power supplies. Today I’ll be showing off two different power supplies though from the same line of products: Straightpower series. What exactly do we have in our lab for you? 450 Watt (BQT E5-450W) and 600 Watt (BQT E5-600W) models.

Most of you are probably aware of the fact that stable rails and low tolerance lead to better system stability. With quad core CPUs around the corner, it’s crucial to feed such devices with power they need. Power (in watts) alone of course won’t cut it. The rest of the story is current which is expressed in amps. General rule of thumb is the more the better. Hardware vendors, especially guys that make CPUs and motherboards will require you to have a power supply with “xx” number of amps for stable operation. By the way, the number increases every now and then as more hungry devices see the day light.

Features & Specifications

Let’s get to what is important to us — stability. Be quiet! Straightpower 400W power supply has two 12v rails while the 600W has 4 of those for better stability. BQT E5-450W can push total of 30A on 12v rail, 30A on 3.3v and 30A on 5v. The higher version of Straightpower can pump 48 amps on 12v rail, 32A on 3.3v and 30A on 5v. The 450W model draws up to 160 Watts under 3.3v and 5v rails combined and 360 Watts for 12v line. With higher wattage, E5-600W version can hold up 170 Watts for 3.3v + 5v rails and 576 Watts for 12V1->12V4 rails (combined).

Main features are common across the whole line of be quiet! Straightpower power supplies. They include Active PFC where voltage is switched automatically depending on what you have in your wall socket, either 115 or 230V — no need for additional switches. Both PSUs are cooled with 120 mm fans with regulated speed. Honeycomb design is a common solution used by most manufactures now, additionally Listan gives you 3 year warranty.

External & Internal Loooks

Design-wise, Listan makes very nice PSUs. Enclosures have a very clean look and slick line. The Straightpower series will look fine in every PC case, especially the ones with side panel windows.

Click a picture to see a larger view

As you can see Straight Power PSUs are inserted into black cartons with cut out piece in the middle to show off its huge fans. Notice handles on the top of the boxes. When you take out the PSU you get blinded by perfect mirror finish look. You can see it in action on the last image. Both Straight Power 450W & 600W units sport 120 mm silent fan with regulated rotation speed. The back features honeycomb design for better heat dissipation. Once again, check out this mirror finish!

Now that we have taken care of the outside, let’s look at the interior parts. Listan and their be quiet! power supplies have been known for good quality components.

Click a picture to see a larger view

First glimpse reveals no differences between 450W and 600W units. However there have to be discrepancies. The 450W model sports two 12v rails while 600W unit four of those. It may not be noticeable, but wire coils are thicker and there is just more wire rolled on. Obviously you will find larger electrolytic capacitors, transformers or resistors. The included silent fan is made by Protechnic, an electric company. The other differences are weight for example. The 600W model weighs a little more than its brother, but the difference is really marginal. Both units are quite heavy which suggests high quality components used.

Bundle, Cabling & Installation

Be quiet! Straightpower power supplies come in very nice boxes with handles. They are well designed with useful information and no wasted space. As for accessories you get a few screws, four thumb screws, velcro straps, zip ties and power cable.

Click a picture to see a larger view

Although Straightpower units use non modular system, they can be easily organized with the included straps and ties. It can get messy, but it’s manageable if you can use most of those cables. An interesting addition to standard cabling are fan wires where you can connect 6 fans that can be controlled by the PSU.

Click a picture to see a larger view

Let’s check the cabling system along with main power connectors. First image shows 20+4 pin power connector (the 4-pin is detachable for those with older 20-pin motherboard sockets). Next up we have CPU power connector which can be split into 2 x 4-pin (or 8-pin). PCI-Express cables are also present and there are 2 of those. This set of wires is available for both BQT E5-450W and BQT E5-600W units. Let’s move down a little and see what else we have.

BQT E5-450W: for this model there are total of six 4-pin connectors, four SATA connectors and one 3-pin FDD connector.
BQT E5-600W: with this power house it’s similar though it’s got eight SATA plugs. The rest stays the same.

While I switch power supplies pretty often, I’ve never had any major problem while installing it. Same applies here. As long as it’s ATX compatible it fits and doesn’t blow up then it technically works (until I take it for a load test). The only thing that bothers me is the mirror finish on those units. It’s not scratch proof so if your hands are shaky you might accidentally tarnish it while fitting it inside your case.


Test rig

  • AMD Athlon 64 Venice running at 1.8GHz and 2.7GHz
  • Stock HSF
  • Six 120 mm fans
  • DFI LanParty UT nF4 Ultra-D modded to SLI
  • 2GB of G.Skill F1-4000BIU2-2GBHV DDR500
  • PowerColor X1950 PRO and XFX GeForce 7900 GT (stock and OC)
  • LiteOn dual layer DVD burner
  • WD 120GB drive
  • WD 40GB drive
  • WD 20GB drive
  • FDD drive
  • be quiet! Straightpower 450W and 600W power supplies
  • Thermaltake MozartTX cube case
  • Windows XP PRO SP2
  • ViewSonic P95f+

Testing conditions

  • Idle: default CPU / GPU speeds, no fans turned on, browsing and listening to mp3s
  • Load: default CPU / GPU speeds, no fans turned on, OCCT torture test, NOD32 scanning in the background
  • Idle OC: OC CPU / GPU speeds, six 120 mm fans turned on, browsing and listening to mp3s
  • Load OC: OC CPU / GPU speeds, six 120 mm fans turned on, OCCT torture test, 3DMark05 in the background
This is likely the most interesting part of any review — testing under different kinds of working environments. The tolarance level for most PSUs nowadays is +/- 5% from the nominal voltage. With that in mind, I recorded minimum, maximum and average rail values (both idle, loaded and overclocked states). Let’s see if those two PSUs stand a chance in real world torture testing.

Both power supplies sport one main transformer. The 600W version uses a split card to feed those four 12v rails which run in parallel. The less powerful one has two 12v rails. I was a bit shocked seeing those PSUs running so close to maximum tolerance level of 5% — especially the 600W model which went up to 4.53% tolerance. I tried to equally feed power to all four rails so I’m definitely not artificially increasing voltage on that 12v rail. As you can see, Straightpower 450W produces more favorable results where it doesn’t go over 4% tolerance.

Things change when I overclock both CPU / GPU and torture them. The change isn’t dramatical however. Twelve volt rails seem to handle the load quite well. Straightpower 600W holds well, but the voltage fluctuates a lot going from 12.55 to 12.59 (never above 12.60 which is a good thing). I can only assume that if you give it a heavier load the 12v rail should calm down a little.


Above, we have consolidated values inside a table. All voltages were averaged to give you a narrower look at the performance against other PSUs.

Be quiet! power supplies have been known for quality built and overall good performance. Personally I’ve had great time testing both Straightpower 450W and 600W power houses. I loaded as much as I could on both PSUs. The good thing was that none gave me any issues. Even the 450W model performed surprisingly well under above conditions. I wish I could throw more at them although that’s about to end with my new über leet PSU tester. That device will draw everything out of a PSU.

Back to Straightpower 450W and 600W. You’ll be happy with either of them, just think of what you’ll run. For Crossfire / SLI however I’d rather recommend the 600W model as it’s a more future proof investment. The 450W version supports dual graphics, but it might “squeak” if you throw a whole lot more at it. Straightpower PSUs are efficient and quiet, but with drawbacks; both produce high voltages for 12v rails. That concerns me as they almost reach the 5% tolerance level. Of course it would be nice to see modular cable system, but it’s hard to get everything in one package nowadays. As for price, those two don’t come with low price tags. If €80 for 450W model doesn’t scare you away go right ahead and order one. The higher-end model costs €20 more (€100) so if you think you might need that extra 150 Watts get that one instead. Neither PSU is available in the United States.

Straightpower 450W & 600W Pros:
+ Plenty of power for running modern PCs
+ Sleeved cables
+ Extra fan connectors
+ Quiet

+ SLI / Crossfire ready

+ Clean look
+ 3 year warranty

Straightpower 450W & 600W Cons:
– High 12v rail voltages
– Voltage fluctuation on all rails
– No modular cable system
– Quite expensive

For good overall performance, grade “A” components and quiet operation, be quiet! Straightpower 450W and 600W models get the rating of 8.5 (Very Good) out of 10 and the Bjorn3D Seal of Approval.

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