OCZ StealthXStream 2 600 W Power Supply Review

1. Introduction2. The OCZ StealthXStream 2 600W (External)3. The OCZ StealthXStream 2 600W (Internal)4. Testing Methodology and Results5. Closing Thoughts6. View All Pages

OCZ have been highly regarded over the years as producing some of the finest memory available on the market and much in the same way as Corsair they have expanded over the years into other hardware markets to enhance their product range.

They have recently updated their StealthXStream range of products and today we are looking at the new 600W unit in their range – the not very creatively entitled ‘StealthXStream 2 600W'. These products are geared for enthusiast users who are working to a tight budget while according to OCZ, still able of delivering high levels of performance and stability.

The OCZ StealthXStream offers Universal Input and Active PFC (Power Factor Correction) to effectively regulate input voltage and they are giving a good peace of mind industry leading 3 year ‘OCZ PowerSwap Warranty'. When this is combined with the ‘PowerWhisper' technology with a large 120mm fan, things are shaping up to be rather promising already.

Technical specifications

• 150 x 140 x 86mm
• ATX12V v2.2 and EPS12V
• OCZ ConnectAll™ universal connectors:
• 1 x 20+4Pin ATX
• 2 x 4-pin CPU (supports double CPUs/supplies stable voltage)
• 2 x PCI-E
• 5 x 4-pin Molex peripheral
• 1 x 4-pin floppy
• 3 x S-ATA
• High efficiency
• 80% @ 115V (Typical load)
• 83% @ 230V (Typical load)
• Overvoltage/Overcurrent/Short-Circuit protection
• Active PFC
• MTBF:100,000 hours
• 100~240Vac 10-5A 50/60Hz
• +3.3V(36A), +5V(30A), +12V1(18A), +12V2(18A), +12V3(18A), +12V4(18A)

The OCZ StealthXStream 2 600W PSU arrives in a subtle blue and black accented box which is both attractive and nicely understated.

The supply is packaged in a chunky section of bubblewrap which offers moderate shipping protection. Ours shipped with a European Power adapter and a user manual. There was also a little pouch of mounting screws. All the bare basics as we would expect at this price point.

The PSU is rather ‘sporty' looking and we like the looks, its a simple plain design which works well – you really can't go wrong with a black paint job and a large black 120mm fan. The Unit is 5.5 inches deep (140mm).

The power supply is not a modular unit so everything is wrapped up in a felt cable tie when you open the box.

OCZ StealthXStream 600W (Cables)

1x Main motherboard 1x 20/24 pin x 1 (46 cm)

1x PCI E 1x six/Eight pin connector and 1x 6 pin (44cm)

4 x Sata Power Connectors (46cm)

2x ATX 12V Connectors (44cm)

3x Molex power connectors (46cm)

3x Molex power connector and 1x floppy (46cm)

Obviously when compared to a higher end product this cable selection seems somewhat limited, but these are built to specific price points. When we look at the older StealthXStream unit this is an identical wiring configuration except the new unit has a single 6 pin and a 6/8 pin PCIe option – the older one was supplied with 2 x 6 pin connectors.

The 120mm fan is branded with an OCZ sticker and there is a specifications sticker on the chassis also.

The fan of choice is a favourite with most power supply manufacturers lately, another 12 cm Yate Loon unit, which is a 12V 0.30A product.

A top down view of the internal structure of the OCZ power supply. This PSU is using two GBU606 rectifying bridges which are connected in parallel and to the same heatshink which is shared by the switching transistors.

These bridges can actually support up to 6A at 100c which in theory would mean that at 80 percent efficiency you should be able to get over 1,100W without any serious damage. If of course the rest of the components were up to the task, which they obviously aren't. This PSU has a total of eight Schottky rectifiers which are attached to the secondary heatsink – all of these rectifiers are MBR3045CT designs which offer 30A maximum current. The older unit used a MBR2045CT combination of rectifiers which only delivered a maximum 20A of current for the 12V output. The power supply is feeding four seperate rails.

The Transient filtering stage can be seen in the picture above. The X and Y Capacitors which make up the second part of the filtering stage can also be seen in close proximity. The primary is controlled by a CM6800 active PFC/PWM combined circuitry panel. The outputs are monitored by a PS223 integrated circuit which supports both under voltage and over voltage protection. It also protects against over current and over temperature situations if they ever occured.

The StealthXStream 2 600W has two transistors in the active PFC circuit and the older one actually had three. This is based around two SPA20n60C3 mosfets and each of these is capable of handling 20.7A at 25c. The electrolytic capacitors available in the secondary unit are Teapo units with a maximum rating of 105C.

The cabling is sleeved well into the unit which is always good to see, this means no possible friction can occur on the bare wires as it enters the chassis. The internal design is clean throughout and the soldering is generally of a very high standard.

The heatsinks that OCZ are using are quite large for a supply with this power output and the relevant areas are shielded. We also noted slightly stronger SPA2060C3 Mofsets used in the switching section which are stronger than the original unit design (around 18A at 25c – they are now 20.7A).

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 25c 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

We are running all four 12V rails into one final test result (12v)

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
115W	1	3.32	1	5.01	8	12.10	1	5.01	0.5	-12.19
355W	4	3.30	4	5.00	26	12.02	1.5	4.95	0.5	-12.02
480W	6	3.27	6	4.97	35	11.95	2	4.91	0.5	-11.86
601W	8	3.19	8	4.91	44.5	11.79	3	4.88	0.5	-11.78

OCZ 600W	Maximum Load
	719.5W

The PSU remained stable, even at full load and the results fall within safe parameters and guidelines. At a sustained 600W the unit was rock solid for many hours. We then cranked our testing equipment to see how far we could push it, the PSU turned off at around 720W which was around 20% over its rated maximum figures. Anything higher and it would shut down immediately. The Overcircuit protection system worked well which is good to see.

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 this unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
115W	10	10	20	15
355W	15	10	25	20
480W	15	15	30	25
601W	20	20	35	25

The ripple results fall well within a ‘pass' rating and these are very good, particularly for a product in such a competitive price bracket.

Efficiency (%)
115W	86.2
355W	87.1
480W	85.4
601W	83.3

These efficency ratings are very close to the figures that OCZ quoted and they are actually within the 80 Plus Bronze certification. OCZ have modestly classed this unit as a 80 Plus Standard certified unit – however we saw peaks of 87 percent at around 280-350W.

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)
115W	27.5
355W	28.9
480W	33.1
601W	38.3

These low levels are very good and only when the unit is loaded to 450W or higher does it become that noticeable. This was obviously in our silent testing environment, under real world conditions with a few case fans you will not hear the PSU until around 75%+ load.

Exhaust Temperature (c)
115W	27
355W	32
480W	37
601W	44

Exhaust temperatures are once again very good indeed and again it only really starts to get warm when at 75% load or higher. When we hit 90-100% load the air coming out of the back of the PSU was relatively warm. Again this isn't a viable real world condition, if you need 600W of constant power, aim higher up the wattage chain.

Maximum load	Efficiency
719.5W	80.3%

Out of interest we lastly decided to measure unit efficency at our maximum rated figure of 719.5W and were pleasantly surprised to see figures of just over 80%. This is not a real world situation incidentally, you would not be running a 600W power supply at 720W long term.

The OCZ StealthXStream 2 600W PSU from OCZ has impressed us, particularly as this is firmly marketed as a budget, value for money unit. Our testing showed that efficiency figures remain high throughout the range with it remaining over 85% efficiency until it reached about 85-90% load. OCZ in reality could have set this up for 80 Plus Bronze approval instead of the bog standard 80 Plus rating they have shipped it with. The unit is stronger than the original design with improved +12 V rectifiers and we liked to see the inclusion of a 8 pin PCIe power connector for modern day graphics card solutions.

The supply remained relatively silent until the upper end of the power delivery and throughout testing it remained unintrusive and reliable, a combination we always like to report. Aesthetically it is also sure to appeal to a wide audience as there are no multicoloured fans or gaudy LED lights incorporated.

Technically the unit is solid throughout all aspects of performance. The ripple results are excellent and the unit falls well within rated specifications, it also managed to maintain strong voltage stability throughout the range. The fact we could easily get another 100w from it without issue means OCZ have been playing it safe throughout the development cycle, meaning that even under reasonable gaming load this will be delivering a high consistency of power.

If we told you this unit only costs £56 inc vat would you be impressed? I know I was.

KitGuru says: This is one hell of a budget oriented PSU which will power the majority of gaming systems on the market.

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