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XFX Pro Series 650W Power Supply Review

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

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
3.36
2.02
5.05
10.03
12.15
0.50
5.08
0.20
-12.11
270W
3.02
3.35
3.01
5.03
19.05
12.12
0.50
5.07
0.30
-12.09
400W
4.04
3.33
5.01
5.02
29.21
12.07
1.00
5.03
0.30
-12.07
523W
6.00
3.31
7.08
5.01
38.14
12.02
1.50
4.99
0.30
-12.05
652W
8.03
3.30
9.02
4.99
48.31
11.98
2.50
4.97
0.30
-12.00

A very good set of results for the XFX Pro Series 650W, all of the primary rails are holding within 2.5% of the nominal voltage.

XFX Pro Series 650W Maximum Load
719.2W

We managed to get around 720W out of the PSU before it would shut down, gracefully. The protection circuitry performs 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 5.05 48.0 12.02 0.2 -12.13 0.50 5.05
145W 12.0 3.29 15.0 5.03 2.0 11.97 0.2 -12.04 0.50 5.03

The XFX PSU handled the Cross loading tests without a problem and we experienced no issues. All the voltages remained within stated tolerances.

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 XFX unit complied with the ATX standard.

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

Ripple results are well within the parameters set down in the ATX12V Ver 2.2 standard. +3.3V and +5V are extremely impressive and the +12V rail is also very stable, never exceeding 30mv.

Efficiency (%)
152W
85.32
270W
86.67
400W
87.33
523W
84.81
652W
83.12

These efficiency results are great for a 80 Plus Bronze certified supply, hitting over 87% at around 50% load. At full load the efficiency drops to just over 83%, which is still very strong.

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
27.6
270W
29.2
400W
29.7
523W
33.8
652W 35.7

At around 70% load, the PSU becomes audible rising to a maximum of 35.7dBa at 100% load. It isn’t the quietest PSU we have tested but at realistic load levels, it will offend no one.

Temperature (c)
Intake
Exhaust
152W
35
37
270W
35
38
400W
38
44
523W
42
50
652W
45
54

The large fan pushes a lot of airflow under load which helps to keep the components in check. At around 70-80% load, the fan speeds start increasing considerably. At full load we reach a 9c above ambient intake threshold.

Maximum load
Efficiency
719.2W
80.3

Pushing the PSU above its rated limits generates an efficiency level of around 80.3%. This is not a viable ‘real world’ situation, but its interesting nonetheless.

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  • Frank

    Cant really go wrong with a seasonic product. quality all the time.

  • Tim

    Great price there. best looking PSU in this price range, without a doubt

  • Tech Head

    Quite a lot of gunk internally there, isnt there? overall seems like a good bronze rated product. solid design, good ripple results.

  • Tom

    under 70 quid for a good quality PSU, very good.

    Gold certified is great, but for the mass market, its too much. a good basic plus is good enough for most people. bronze is better but still priced well. cant be bad to it.

  • Eric K

    price is the selling point. specs are decent. performance is solid. only issue I see is complete market saturation in this price point. everyone has at least 2 models in this price range. tough to get sales.

  • harry

    Thisis right up my alley, especially the price for such a quality unit. ordered one 🙂

  • Jonathon

    More than enough for most people. I find it hard to believe that people would pay 250 quid for a pSU today.

  • Jerry

    Seasonic do it again 😉

  • Joe

    The packaging is typical XFX, stands out a mile. people might laugh, but in a shop its the first thing you look at.

  • Tech Head

    Its a good point Joe, but I wonder the percentage of sales in 2010 from stores. Online is surely where the heart of sales come from.