FSP Aurum CM Series Gold 650W PSU review

1. Introduction2. FSP Aurum CM Series Gold 650W (Bundle & Cabling)3. FSP Aurum CM Series Gold 650W (External)4. FSP Aurum CM Series Gold 650W (Internal)5. FSP Aurum CM Series Gold 650W (Super High Res Gallery)6. Testing Methodology & Results7. Closing Thoughts8. View All Pages

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. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 35c) in our environment to greater reflect warmer internal chassis conditions.

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
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

We are combining 12V output into a single result.

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
152W	2.07	3.38	2.07	5.00	10.13	12.08	0.50	5.01	0.20	-12.03
270W	3.03	3.35	3.05	4.97	19.12	12.02	0.50	5.00	0.30	-12.00
400W	4.01	3.32	5.02	4.86	29.16	11.93	1.00	4.97	0.30	-11.97
523W	6.03	3.26	7.03	4.79	38.18	11.86	1.50	4.91	0.30	-11.91
652W	8.09	3.22	9.00	4.67	48.04	11.77	2.50	4.85	0.30	-11.86

Load regulation of the FSP power supply didn't impress us, with the +5V output in particular causing a concern, at 400W it dropped to 4.86V, falling further to 4.67V at full load, which is below the recommended ATX specifications of 4.75V. The +12V output dropped to 11.77V at full load which isn't quite as concerning, but nonetheless is still far from ideal. The +3.3V output dropped to 3.22V at full load.

Not a wonderful set of results, especially for such an expensive unit.

FSP Aurum CM Series Gold 650W	Maximum Load
	702.3W

The power supply would shut down at 702.3W, gracefully. The protection circuitry worked well.

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
590W	1.0	3.32	1.0	4.97	48.0	11.75	0.2	-12.03	0.50	5.00
145W	12.0	3.21	15.0	4.69	2.0	12.02	0.2	-12.01	0.50	4.98

Again, the +5V output raised an eyebrow, dropping to 4.69V when hit with 15amps. This really is a concern for ultimate stability, even though it didn't shut down for us.

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 unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
152W	10	10	25	15
270W	10	15	30	15
400W	15	20	35	20
523W	20	20	45	25
652W	30	25	55	30

Noise suppression is far from class leading, although they all fall within the rated guidelines, by a clear margin. That said, the +3.3V output peaked at 30 mV, and the +12V output peaked at 55mV under full load. Not the best results we have seen recently.

Efficiency (%)
152W	88.12
270W	89.23
400W	90.89
523W	90.12
652W	88.32

Efficiency is decent for an 80 Plus Gold Certified unit, peaking just under 91 percent around 50-60% overall load. These are far from class leading in this category, but still good.

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 Power Supply we have taken it into our acoustics room environment and have set our SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa) 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)
152W	28.3
270W	29.7
400W	32.4
523W	34.2
652W	35.1

The fan in the FSP power supply is quite good, and almost silent until around 400W load, when it spins up, generating around 32.4 dBa. At full load this rises to 35.1 dBa, meaning it is clearly audible.

Temperature (c)
	Intake	Exhaust
152W	36	38
270W	37	41
400W	38	46
523W	42	52
652W	45	58

The 120mm fan delivers decent results, although at full load exhaust temperatures rise to a 13+c above ambient threshold. Again, not the best results we have seen in the last 12 months.

Maximum load	Efficiency
702.3W	86.4

Pushing the PSU above its rated limits generates an ultimate efficiency level of around 86.4%. This is not a viable ‘real world’ situation, but its interesting nonetheless.

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