Corsair CS450M PSUThe Corsair CS450M (CP-9020075) power supply is an entry level gaming model that we procured for a refurbished machine. The old AK-680 PSU had dual 12V circuits which limited the use of advanced gaming grade video cards somewhat. The CS450M uses a single circuit to eliminate confusion about cables and loading.

The CS series are designed to replace the now obsolete CX, TX and VS series which are 80 PLUS bronze etc. The CS series are 80 PLUS gold which is more energy efficient.

The Corsair CS series offers the CS450M, CS550M, CS650M, CS750M and CS850M. The top model has adequate power and cables for a pair of single GPU cards in SLI or CFX configuration. We chose the entry model as the machine the CS450M will be installed in uses the CP-9020075 which uses very little power.We noticed that the Corsair is now using Great Wall (China) to manufacture their CS series.

The CS450M is the standard ATX, 86mm by 150mm at the back panel, to fit the standard ATX screw positions. The CS450M is 140mm long matching standard ATX.

The CS450M fan is 120mm which is all that is needed for a 450W 80 PLUS Gold model. So little waste heat is generated that many users may find the fan hardly noticeable as Corsair designs their power supplies generally with variable fan control.

The CS450M uses a single 12V circuit with 35A of current capacity. The available 12V capacity beyond the old AK-680 it replaced. The difference between the two PSUs is stark.

There are few cables with the CS450M as this PSU is designed for more basic machines. The single PCI Express cable limits the video card options. Cards like our EVGA GTX 660 Ti FTW Signature 2 would need an adapter to be able to provision both 6-pin PCI Express connectors. Adapters are inexpensive. The CS450M is more suited towards mainstream video cards.

The CS450M is really a 12 V PSU. The legacy 3.3V and 5V lines are perfunctory and modern power supplies are rated for overall power with heavy weighting to 12V capability. The design changes make the CS450M less costly to manufacture which improving the overall efficiency.

The semi modular design makes sense. The perfunctory 2×12 motherboard cable and EPS12V cable are always installed. What varies is the range of peripherals. This design makes the cable management slightly more manageable.

The CS450M features an industrial looking paint scheme. Using the green lettering for the trim gives the impression of a safe design. Given the efficiency it seems appropriate.


  • ATX 2.31
  • EPS12V 2.91
  • Yate Loon D12SM-12 120mm sleeve fan
  • single 12V rail with 35A capacity
  • flat modular cables
  • automatic input power configuration
  • 80 PLUS gold
  • 3 year warranty
  • RoHS Compliant

The CS450M features complete protection. Over current (OCP), over voltage (OVP), over power (OPP), under voltage (UVP) and short-circuit (SCP, tested and working) protections.

Corsair CP-9020075 ATX Power Supply
AC Input: 200V – 240V DC Output +3.3V +5V +12V -12V +5Vsb
Current: 8A Max Load 20A 20A 35.5A 0.8A 3.0A
Frequency: 50Hz – 60Hz Maximum Combined Wattage 100W 270W 10W 15W
Total Maximum Power: 450W


  • US ATX Power Cable
  • ATX 2.x 20+4 connector
  • Single ESP12V 4+4
  • 1x PCIe 6+2
  • 2x SATA strand with 2 connectors
  • 1x Molex strand with 2 connectors
  • 1x Molex to Berg adapter

The cable bundle is excellent with long cables to support larger EATX chassis. All of the cables are flat and east to use. The connectors are also excellent and are easy to attach. The cables seemed to be ideal in length when the CS450M was installed in our ATX chassis.

The modular cables are the same type as used with the Corsair RM series, AX Platinum series and the value oriented CX-M series.

The PCI Express cable connector on the CS450M is also designed for EPS12V. We have noticed a few motherboards with a pair of EPS12V headers, which suggests they need more power than even the 8-pin connector can provide. Obviously the CS450M is not not designed for such a demanding workload, but it does provide an outlook towards where modern motherboards are headed.


The CS450M is a very strong performer that is well suited to a modern machine. The efficient design means very little noise or excess heat is noticed.

Loaded to 400W the CS450M fan does run hard and the USB thermometer did recognize some warming of the exhaust air.

We consider the CS450M to be a solid choice for mainstream machines with a single video card. The single rail for power means any configuration is well provided for. The PSU can connect up anything from an old Pentium machine on up to the latest Skylake.

At the price the CS450M competes at is loaded with a lot of models. For the average $90 price there are higher capacity models, but the 80 PLUS gold mitigates this considerably. Very few 80 PLUS gold models are available for under $99 in 2015 however we do expect that older inefficient designs will slowly disappear.


The CS450M uses a 120 mm fan which is very quiet when the load is under 25% and only begins to become noticeable when the unit is loaded hard.  The Yate Loon D12SM-12 has a rating of 100 CFM for airflow. The fan generally does not work hard as the high efficiency eliminates the load.

The CS450M has thermal controller for the fan which generally leave the fan at a very low operating speed. Its only when the power draw exceeds 50% that we noted the fan start to spin up.


Our Corsair CS450M is rated for 450W at 40°C which is very realistic. A PC PSU runs hot loaded so anything that is not rated at 40°C or more is not suitable. We use digital thermometers and these can continuously monitor temperatures. The CS450M is designed to be installed into any ATX chassis, top or bottom mounted.

The thermometer has showed the exhaust air from the CS450M to be barely above ambient. Even loaded to 50% has not effect on the heat and its only near 100% that pushes the fan faster. Clearly the high efficiency means far less waste heat as compared to older obsolete power supplies.


MSI does not offer voltage monitoring in the BIOS however we do have a digital multimeter. The oscilloscope also shows the CS450M to be extremely clean and nicely centered on the target voltages.


3.3V (orange) 3.322V < 1%
5V (red) 5.033V < 1%
12V (yellow) 12.014V < 1%

Obviously the CS450M achieves precision far beyond the required specifications in the ATX manuals. Its clear that Corsair worked hard to design a quality power supply. Generally enthusiast power supplies have been far beyond the old ATX requirements for many years.


Testing the CS450M with the P4400 showed the PSU to have an excellent power factor above 99% at all loads. Better power supplies use active filters which can reach 99%. Cheaper power supplies all use a simple low pass filters which can barely reach 70% which is one of the reasons they are so inefficient.


Connecting our handheld oscilloscope to the 12V line show ripple levels were so low we had to zoom in 3 times to see it. The ripple is well under 50mV which is excellent. Clearly excellent quality capacitors and MOSFET’s are needed to achieve such good ripple values. Our low cost oscilloscope costs under $100 and its ideal for PSU testing and general RF use. Agilent oscilloscopes cost over $25,000 and are intended for large engineering shops and are excessive for a PC gaming review.


The CS450M provides 15W of standby power to be able to support USB hubs in the event a keyboard is connected to one. Many power supplies are very inefficient with the 5 V standby circuit. The CS450M manages about 75% on the 5V standby which is much better than most rivals. The front USB 3.0 ports are powered when the machine is powered down, so its possible to charge a mobile phone or MP3 player without powering up the machine.

The CS450M is also able to achieve the 1W standby when a matching motherboard is used. The M5A99FX and 970A-G43 support the latest standards making it a good match.

USB 3.0 ports are widely provisioned with additional power to support charging mobile devices. Charging can be done with the machine powered down or on standby. Low cost boxes for the old 3½” bay are available at low cost and larger models are available for larger 5¼” bays for those using older chassis.


The CS450M is certified 80 PLUS gold. This means it must be 87% efficient at 20%, 50% and 80% loads. As the graph shows the CS450M is a very well designed and efficient model. The top curve shows 220V while the bottom shows 115V service.

CS450M-EFFICIENCYThe curve shows that the CS450M, like all power supplies, is more efficient with 220V. Its also is most efficient at around 50% load which is also very typical.


Corsair provides a 3 year warranty on their CS series power supplies. This can be done due to the very high quality components used. We noticed many parts previously only seen on more expensive models are used in the CS450M. This suggests Corsair wanted to deliver a better quality product into the hotly competitive market.

Because Corsair rated their PSU at 40°C  we are confident in the quality of the product. 40°C  is much more reflective of real world conditions. We would like to see the whole industry use 50°C as a standard for testing only because it can be hot in the summer in the tropics.

Most gaming machines run cooler due to good air flow, but many machines have few fans so the overall operating temperatures are higher. We strongly recommend using at least one front fan and one rear fan to keep a desktop machine running cool.


Many PSU vendors claim that their model is 500W but these vendors include 3.3  and 5V capacity in duplicate. Corsair and other respectable vendors only state the important 12 V capacity which is what matters to a PC gaming rig. After all the 3.3V and 5V are drawn from the 12V line. This is why 12V matters. See the review of the AK680.

Because Corsair claims realistic power capacity, we strongly recommend them. This way when selecting a video card and when the power requirements are checked, the rating of the Corsair PSU will be consistent with the gaming video card requirements.

Corsair has earned a reputation for better quality power supplies. They are somewhat more expensive, but the value is stellar. The CS450M has been a hot seller as many have upgraded their machines to be 80 PLUS gold.


We have installed the CS450M into a standard ATX chassis. The PSU is  top mounted right-side up so that the cable bundle easily fits the slot. The cables easily reached the various connections suggesting this PSU cable set

The MSI 970A-G43 motherboard has enough fan headers that Molex cables are not needed. Fan controllers are a popular option with machines that lack adequate motherboard headers. The AMD Athlon II X2 250 has a TDP of 65W but dynamic power management means the real average load is much lower.

The Asus EAH5450 512MB presents a minimal load which means the CS450M is near the most efficient sweet spot. The CS450M is capable of running a video card with a single PCI Express power cable.

We tried the BFG GTX 260 MaxCore 55 with an available adapter to connect the second PCI Express and the machine booted without problem using the 65W Athlon CPU. Even with this card running Furmark was not able to cause the CS450M to warm up much or shut down. This suggests that the Corsair could have added a second PCI Express cable connector to support 200W video cards. Modern video cards have dynamic power control which means that the overall load stress a PSU experiences is minimized.

We have noticed some 28nm video cards (R9 270, GTX 750 Ti) with a single 8-pin PCI Express card and we expect that may become more common with 14nm. This approach also makes cable management much easier. DX12 with the explicit multiple GPU support means that extreme setups will be possible. The CS450M however is more suited to a basic media center machine.

We installed several hard disks into a refurbished machine and the CS450M had no problems with even 6 disks powering up when using the EAH5450 for a display card. Even expensive NAS boxes lack the capacity for as many disks. Idle hard disks use less power ar the cost of lag to access.


Assuming that the old AK-680 is 60-70% efficient and the CS450M is 87% efficient we can develop a table of savings at all power levels. Saving 100W of power load amounts to 438 kWh in savings assuming 24/7 operation. At 11 cents per kWh, 438 kWh costs approximately $48.18. Most pay more than 11 cents per kWh making the CS450M even more desireable.

The state of California has much higher electric costs compared to us (14 cents per kilowatt hour) and the payback period would be far shorter. Hawaii has brutal electric rates of around 32 cents per kilowatt hour magnifying the savings even more. The EU pays very high electric rates and and as rates get higher the payback time get shorter and shorter.

Power plants are expensive and sometimes hard to place. So power companies work with the EPA to develop solutions and over the decades the work has saved the need for hundreds of power plants. Consumers also benefit with reduced energy costs.

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