CoolMax CU-700B 700 Watt Modular Power Supply

Coolmax Technology, Inc. is a rapidly growing company that was founded in the year 1997. Our initial task of providing cooling solutions for electrical and industrial applications using AC and DC voltage fans is our solid foundation. Our commitment to excellence in both products and service had earned for us the reputation as a leading thermal solutions provider in the industry. We strive to work hard, hand in hand with our clients, from the biggest to the smallest. They rely on our company's ability to provide quick and professional responses to inquiries and production demands. Our factories are located in China and are ISO9000 and 14001 certified, all our products are UL, TUV, CSA, CE approved. Coolmax is dedicated to providing the best cooling solutions engineered for a high-tech world while maintaining long-term customer relationships. Source: Coolmaxusa.com 

CoolMax is a fairly new name in the power supply market.  Their monstrous 1350 Watt power supply has won them many awards and has high praise.  This is my third time reviewing a CoolMax product, their past two products were alright, but not great, so lets see how this one performs and what is included in the box.  Today, we are taking a look at the CU series from CoolMax.  This particular model is the CU-700, which has a 700 watt power rating, and is modular.  CoolMax has recently licensed the modular technology from Ultra Products and the CU-700 is one of the power supplies to utilize it.

Upon opening the box, you will find no users manual, just a piece of paper with a website link (what happens if the user has no computer to look up the manual, except for the one that they are building with this power supply?) a very thin and short power cable, no screws, and a bundle of modular cables.  I am beginning to get worried about the quality of this power supply!

Here are some of the main features and specifications from CoolMax's Website:

The Power Supply:

The power supply features a traditional matte black colored housing and with a silver colored fan grill.

Looking at the side of the power supply, there is a CoolMax label with their logo on it, the model number and a condensed specification list.  Note that there are three +12v rails, with the +12v1 rail supplying up to 18 Amps and the +12v2, +12v3 rail supplying up to 16 Amps each.   The 3.3v supplies up to 28 Amps and the +5v supplies up to 28 Amps.  This power supply does not have 80Plus certification, and I doubt that this power supply can be 80%+ efficient, you'll see why later on.

There is an large grill on the back which allows the 120 mm fan to exhaust hot air, an on/off switch and AC Power Input.  This power supply does not appear to feature Active PFC, so there is a red colored switch to allow the user to switch between voltages.  I am surprised, since this is the first power supply that we have reviewed that has this kind of switch and makes me concerned yet again about the quality of this power supply.

The modular connectors on the CU-700B are placed neatly on the back.  There is one red PCI-e connector, two SATA connectors, and four peripheral (molex) connectors. 

Here is something I do not like.  The pins for the SATA modular cables are poking out and can easily be shorted out by something nudging against it.

This power supply features the following cables:

Here is another thing that concerns me.  The cables are really short, with the 24-pin cable being about 11 3/4 inches long and the attached 6-pin PCI-e, 8-pin EPS power connectors are about 9 inches long.

-A 24-pin ATX power connector

-A 4/8-pin +12v CPU/EPS Power Connector

-2x 6-Pin PCI-Express Power Connectors

-Oh no! One of these grips from the molex connectors broke off during testing.  The plastic is cheap feeling and brittle.  Another one of these grips already fell off upon opening the box.

-4x Molex Power Connectors

-4x Serial ATA Power Connectors

-1x Floppy Power Connectors

Cooling:

There is a 120mm fan on the bottom of this power supply.  During testing, at idle loads, this fan is somewhat quiet, making a slight whining sounds. With loads, the fan sped up a lot, making a whirring sound.  The noise while loaded was acceptable, but was able to be heard over the system fans, which are nearly silent.

Inside the Power Supply:

* Taking this power supply apart will void the warranty.

Inside the power supply,  there are two silver finned heat sinks, to cool down the voltage rectifiers.  The main transformer is near the middle of image, while the smaller transformers are above it.  The primary capacitors are Micon, while the secondary capacitors are also Micon branded.  I have never heard of the capacitor brand, which is not good.  Also the primary capacitors and their close proximity to the 115v/230v voltage switch wires makes this power supply appear not to have Active PFC.  It has no power factor correction board or logic at all.  This also must mean that its efficiency is pretty low.

The primary capacitors are Micon branded.

The secondary capacitors are also Micon branded.

The fan inside is a Cool Max branded fan. It has the model number 1225L12S ND1 with a maximum draw of 0.40A.

Testing:

For this power supply, the test system consists of the following:

-Antec Nine Hundred Two Case

-Intel Core 2 Quad Q6600 Quad Core Processor @ 3.4 GHz (1.40v)

-ZeroTherm Nirvana 120 Heatsink

-eVGA nForce 680i SLi Motherboard

-4GB (2GB x 2) of OCZ Platinum DDRII-1066 Memory

-320GB x 4 Western Digital 7200RPM 16MB Cache Hard Drives

-2x nVIDIA GeForce 8800GTS (G92) Video Cards @ 715MHz Core / 1000 MHz Memory

-Sound Blaster Live! 5.1 Digital Sound Card

-Asus 16x DVD-RAM / 18x Samsung DVD-RAM Drives

-4x 120MM fans, 1x 200mm fan

-2x CCFL Lights

(Multimeter Results)

*For additional / larger pictures of the CoolMax CU-700B, Click Here

*Voltages are at a 'Max Load' for a typical gaming computer, running Orthos, Sisoft Sandra Hard Drive benchmark and 3DMark06 CPU Test 1 and 2 / Deep Freeze HDR test, and read with a Multi-Meter.

Capacitor Brands:

Primary: Poor / Unknown

Secondary: Poor / Unknown

Primary: Micon

Secondary: Micon

Voltage Results:

-The +12 voltage result was bad, it fluctuated between 11.76v and 11.93v during the tests, while the 3.3v and 5v rails were fine.

Stability Results:

-The system became unstable and froze during the Deep Freeze HDR test, so I had to restart the system a couple of times.  All the power supplies I have reviewed in the past did fine for the duration of the tests.  If I took out one video card and put the CPU at stock speeds, it would run fine.  But, I should not have to compromise the test system's performance to suit the output of this '700 Watt' power supply.

Fan Speed Impressions:

-During the tests, the fan speed revved up to high speed and stayed there until the system was idle again.  The noise overpowered the system fan noise.

Installation:

-Installation of this power supply itself went badly.  There were numerous problems such as the cables being very short, not even able to reach my motherboard's 24pin power connector.  It was stretched heavily across the motherboard as well, causing unnecessary stress on the cable.  The 8-pin EPS power cable was also too short, since the connector is on the top left of the board. I had to leave the power supply dangling in the bottom of the case during testing.  Also a few of the molex grips broke off.

Conclusion:

This power supply is the first one that I have reviewed that could not keep my test system stable.  Installation was also a bad experience, where the power cables could not be connected on my motherboard.  I can only suggest this power supply for system builders with a micro ATX case and for builders that do not have a high powered system.  I thought this was a 700 Watt power supply, but clearly it is not.  At best, it is a 400 watt - 500 watt PSU.  It lacks the proper length of cabling and amount of connectors as well.  Overall, the power supply has a cheap feel to it and does not perform well.  A few good things about the CU-700B is that it is quiet at idle loads, has modular cabling, and a five year warranty.  It is offered at around $60, which is about average for a 700 watt power supply.

Pros +

-Modular

-Five Year Warranty

Cons -

-Fan becomes noisy with loads

-Cheap materials used

-Broken molex grips

-Short cables

-Terrible performance for a 700 Watt power supply

Techaddicts.net would like to give this power supply a Bad rating.

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