Corsair TX 750W V2 Power Supply Review

1. Introduction2. Corsair TX750W V23. Corsair TX750W V2 (Internal)4. Testing Methodology and Results5. Closing Thoughts6. View All Pages

A couple of weeks ago KitGuru reviewed the Corsair TX 850W V2 power supply and we walked away with positive impressions. The 850W TX V2 met the high standards that we all expect from a Corsair product. The TX V2 range is designed for enthusiasts who need a high quality power supply but who don't need modular cabling which can be disconnected from the main unit.

The TX range from Corsair won many awards worldwide and the Corsair TX V2 range already looks set to be just as successful. These new supplies combine 105c Japanese capacitors, with solid load regulation and a large 140mm fan.

The new TX V2 power supplies also offer increased energy efficiency, rated 80 Plus Bronze with ErP compliancy. Corsair have also spent time reducing the noise levels when compared directly to the original TX series.

Corsair Enthusiast Series TX750 V2 Features:

• Conforms to the latest ATX12V v2.31 and EPS 2.92 standards, and is backward compatible with the ATX12V 2.2 and ATX12V 2.01 standards
• A dedicated single +12V rail offers simple configuration and maximum compatibility with the latest graphics cards and other components
• An ultra-quiet, 140mm double ball-bearing fan delivers excellent airflow with exceptionally low noise levels by varying fan speed in response to temperature
• Complies with the European Union ErP Directive (2009/125/EC) so the power consumption of the whole system, in either standby or off mode, can be less than 1W when used with a properly configured, ErP-compliant motherboard
• 80 PLUS® Bronze certified, delivering up to 85% energy efficiency under real-world load conditions
• Active Power Factor Correction (PFC) with PF value of 0.99
• Universal AC input from 90~264V
• Over-voltage, under-voltage, over-current, and short circuit protection provide maximum safety for your critical system components
• High-quality Japanese capacitors provide uncompromised performance and reliability
• A five year warranty and lifetime access to Corsair's legendary technical support and customer service
• Safety Approvals: UL, CUL, CE, CB, FCC Class B, TÜV, CCC, C-tick

The Corsair TX 750W V2 arrives in a stylish box which features a sepia style image of the PSU on the front. We always like the Corsair box design.

The TX750 is well packaged, sandwiched between two foam inserts and wrapped in a felt bag.

The TX750 V2 ships with a power plug, mounting screws, Corsair branded sticker and cable ties.

The TX750 looks identical to the TX850, with clean, simple fonts and an orange accent to the right.

As this power supply is not a modular design, all cables enter the chassis from the front. They are supplied with a hefty cable tie around them for transportation.

Model	CMPSU-750TX V2
	AC Input Rating
AC Input	90-264V
Input Current	6-12A
Frequency	47-63hz
	DC Output Rating
	Max Load	Max Output
+3.3V	25A	150W
+5V	25A
+12V	62A	744W
-12V	0.5A	6W
+5VSB	3.0A	15W
Total Power	750W (continuous @ 50c ambient temperature

The deep matt paintwork is top quality, meaning that it wont chip or mark easily. The 12V rail is strong, delivering 62A.

Connectors	CMPSU-750TX V2
ATX Connector	x1
EPS Connector	x1
PCI-E Connector	x4
4 Pin Peripheral Connector	x8
SATA Connector	x8
Floppy Connector	x2

The fan is a Yate Loon D14BH-12 140mm unit which can spin up to 2,800 rpm while pushing 140CFM. The maximum noise is rated by the manufacturer up to 48.5 dBa, but we doubt it will get close to this, even under full load. This is however a seriously high performance fan and a great choice by Corsair. The same fan is used in the TX850W V2.

The overall design of the power supply is very clean with oversized heatsinks helping to ensure that temperatures remain within parameters. The 750W TX V2 is tested and guaranteed to deliver its rated specifications at an ambient temperature of 50c.

The 750W Corsair uses a 400/220uF and a 400/330uF capacitor, rated to 105c. The TX V2 series utilises under and over voltage protection to ensure that the 3.3v, 5v and 12v outputs do not exceed specific levels, potentially causing damage. Over Current Protection, Over Temperature Protection and Over power protection are also incorporated along with Short Circuit protection to shut down the PSU if any of the rails short.

The cabling is fully sleeved for protection against long term fraying, and it is secured with cable ties.

Additional technical assistance: Peter McFarland and Jeremy Price.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. Over the coming months this configuration is likely to be adjusted further and fine tuned. Ambient room temperatures are kept to a ‘real world’ realistic condition of 23c with air conditioning.

We use combinations of the following hardware:
•  SunMoon SM-268
•  CSI3710A Programmable DC load (+3.3V and +5V outputs)
•  CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
75W	1.22	3.35	1.19	5.12	4.90	12.08	0.50	5.05	0.20	-12.07
150W	2.18	3.34	2.80	5.09	10.00	12.07	1.00	5.03	0.30	-12.08
375W	6.15	3.32	6.00	5.07	26.10	12.06	1.50	5.02	0.50	-12.09
565W	10.30	3.30	10.87	5.05	38.34	12.05	2.00	4.99	0.60	-12.12
750W	10.74	3.28	13.86	5.04	53.51	12.02	3.00	4.97	0.80	-12.12

The TX750 delivered excellent load regulation on all output channels across a wide range of loads. These are great results and the +3.3V and 5V rails remained firmly within +/-2% of the nominal voltage instead of the recommended +/-5% and the +12V rail held within +/- 1%, even when it was forced to deliver over 53 Amps.

Corsair TX750	Maximum Load
	834.9W

We managed to reach around 835W before the TX750 V2 would shut down gracefully.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
734W	1.0	3.33	1.0	5.05	60.0	11.97	0.2	-12.04	0.50	5.00
154W	15.0	3.27	15.0	4.97	2.0	12.05	0.2	-12.07	0.50	5.02

Much like the TX850 V2, the fluctuation is held safely within the rated parameters, even when we load the 12V line with 60A.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.

ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the Corsair unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
75W	5	5	10	5
150W	5	10	15	10
375W	10	10	25	10
565W	10	15	30	15
750W	15	15	35	15

Ripple results are very impressive, across the board. The 12V rail registered around 35 mV at full load with our equipment, which is well within the Tolerance guidelines.

Efficiency (%)
75W	83.43
150W	86.57
375W	87.45
565W	85.13
750W	84.21

For a 80 Plus Bronze specified unit, these results are very strong, showing a maximum efficiency rating of 87.45. At maximum load this drops to around 84.67%, which is again, a great result.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the Corsair Power Supply we have taken it into our acoustics room environment and have set our Digital Sound Level Noise Decibel Meter Style 2 one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.

KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refridgerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
75W	28.6
150W	29.3
375W	31.3
565W	36.2
750W	40.1

Noise levels are low, with the system only becoming audible in the final 25% of output. Under 450W load it would be hard to know the unit was actually on.

Temperature (c)
	Intake	Exhaust
75W	35	37
150W	36	39
375W	39	45
565W	42	51
750W	44	54

Exhaust temperatures are good, rising to a 10c above ambient result at full load. The 140mm fan works hard in the last 15-20% of output, but the temperatures are fairly well maintained.

Maximum load	Efficiency
834.9W	80.8

For those interested, we measured efficiency when stressing the unit to breaking point. Over 80.8% at 835W … hardly practical, but interesting regardless.

The TX750 V2 is another great power supply from Corsair which is a big improvement over the predecessor. Not only does the supply look fantastic with the stylish and durable matt paint, but the overall design implementation is first class.

The internal components have all been carefully selected to ensure long term stability, with capacitors all rated to 105c. Our tests have highlighted that the cross loading and output regulation is stellar and the ripple results are excellent, a somewhat common trait of Corsair selected designs.

The noise levels are also good, until they are pushed to the limits of power output, when the fan works overtime to keep the temperatures within specification. That said, it is not practical to be running a power supply within the top 10% of its power output on a regular basis.

Unlike the AX power supplies, the TX range has a focus on hitting mainstream price points. The TX750 retails for £96, identically priced to the original design, offering excellent value for money. The 80 Plus Gold certified AX750W by comparison costs £133 inc vat.

KitGuru says: Combines fantastic build quality with great performance results and a 5 year warranty.

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