Corsair's CX series consists of both non-modular and semi-modular units. It was recently upgraded with new members and improved versions of older ones. The CX650M is the third strongest member of the line, featuring 650W capacity and a 40°C rating.
The CX650M is among the best bang for the buck PSUs available on the market today. It offers very good performance and it is silent enough, although it could be even more silent with a lower, minimum fan speed. At its current price it is very difficult to find a better unit, covered by a hefty five-year warranty.
Pros
+
Price
+
Full power at 45°C
+
Ripple suppression
+
Load regulation
+
Silent and efficient (for a Bronze unit)
+
Hold-up time (with 470uF bulk cap)
+
5VSB efficiency
+
4x PCIe & 1x EPS connectors
+
Warranty
Cons
-
Sleeve-bearing fan
-
Fan speed at light loads could be lower
-
3.3V rail performance in Advanced Transient Response tests
-
Inrush current with 115V input
-
Power Ok signal's hold-up time
-
Distance between peripheral connectors
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Corsair CX650M Power Supply Review
High-end PSUs might offer top-notch performance, but the models that drive sales are much more affordable. Corsair's CX family is the company's mainstream line-up. It's one step above the entry-level VS series, which we don't even have access to in the U.S.
The CX portfolio includes modular and non-modular products; the former is distinguished by the CX-M brand. There are five CX-M units in total with capacities ranging from 450 W to 850 W, covering the most popular categories. All of them feature 80 PLUS Bronze efficiency and have a 40 °C temperature rating for continuous full-load delivery.
In addition, Corsair backs them with a five-year warranty. That's impressive for a mid-range PSU family, exhibiting confidence in the Channel Well (CWT) platform it employs. The upgraded CX-M models are interesting enough, though we have to wonder about their higher than expected prices. We don't doubt that upgrades affect manufacturing costs. Higher temperature ratings and improved reliability require quality components, after all. But we do consider PSUs a real investment, since they keep your system running safely and efficiently. So we recommend against buying dirt-cheap power supplies just to save some money. That gamble rarely pays off.
Besides the semi-modular cable design and 40 °C temperature rating, the CX650M also features a single +12V rail and sleeve-bearing fan that promises quiet operation. Since this is an 80 PLUS Bronze unit, there is no semi-passive mode. Lower efficiency results in higher thermal loads compared to Gold- and higher-rated PSUs. In general, fanless operation isn't recommended in low-efficiency PSUs, since it stresses sensitive components and doesn't last long anyway. It's better to play it safe in this segment. If you desperately need a passive mode, then you should look for a higher-efficiency PSU.
Specifications
The CX650M is compatible with Intel's C6 and C7 sleep states, since it uses DC-DC converters for generating the minor rails. In addition, it is equipped with a full set of protection features, including over-temperature protection, which we consider a must-have. The CX650M's dimensions are compact, thanks to a reduced depth of only 14cm.
As mentioned, there is no semi-passive mode and Corsair claims compatibility with the latest ATX spec (v2.4). Finally, the provided warranty lasts five years. We're comfortable with that coverage. Interestingly, the CX650M's price on various online stores is way lower than the company's official MSRP. For its own reasons, Corsair lists an estimated price much higher than a Bronze-rated PSU should sell for. It's a good thing street pricing is more sane.
Power Specifications
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Rail
3.3V
5V
12V
5VSB
-12V
Max. Power
Amps
25
25
54
3
0.8
Watts
130
648
15
9.6
Total Max. Power (W)
650
The single +12V rail is quite strong, sporting a maximum current of 54A. The same goes for the minor rails, which can deliver up to 130W, combined. Finally, the 5VSB rail has sufficient capacity for this wattage category.
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Cables And Connectors
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Native Cables
Description
Cable Count
Connector Count (Total)
Gauge
ATX connector 20+4 pin (590mm)
1
1
18AWG
4+4 pin EPS12V (640mm)
1
1
18AWG
Modular Cables
Row 3 - Cell 1
Description
Cable Count
Connector Count (Total)
Gauge
6+2 pin PCIe (600mm+150mm)
2
4
18AWG
SATA (350mm+120mm+120mm+120mm)
1
4
18AWG
SATA (490mm+120mm)
1
2
18AWG
Four-pin Molex (450mm+100mm+100mm) / FDD (+100mm)
1
3 / 1
18AWG
The PSU features semi-modular cabling with only two native cables. That's perfectly acceptable, since every system needs them anyway. Cable length is ample, but the distance between peripheral connectors is too short. Moreover, the FDD connector isn't provided in adapter form, but is instead installed onto the cable that hosts the four-pin Molex connectors. This is a shame, since most folks won't even use a floppy drive.
The number of PCIe connectors is ideal for a budget-oriented 650W power supply. And as a result of the low street price, we won't whine about the single EPS connector. We could use a couple more peripheral connectors, though.
Power Distribution
Since this PSU features a single +12V rail, we do not have anything to say about its power distribution.
I have several CM and CX-M units, which I plan to fully evaluate. So far I figured that there are differences (something natural of course) in their performance.
The 750W and 850W CXM units are basically unchanged except for a bridge rectifier upgrade. Everything else is the same. Only the CX450-650M got the major revisions.
