Zalman 850W Heatpipe Cooled PSU

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Product: Zalman ZM850-HP 850W PSU
Provided By: ZalmanUSA
Price: ~$195CDN - Online

 

Introduction:

There are several schools of thought when it comes to Power Supplies and voltage rails.  One group of people insists that you need a large number of 12v rails in order to ensure stability across the entire platform.   The other group states that a single or a couple of larger 12v rails perform better than many rails with lower amperage.  Today we are looking at the Zalman 850W PSU and will put this debate to the test as this PSU has a total of six 12v rails that each provides 18A and a total of 720W across the 12v lines.  We will be putting this PSU to the test in the most demanding system we've built to date and manage to consistently pull 650W in a full-load situation.  This PSU sweats, but does it break down and beg for mercy?  Keep on reading to find out.

PSU Box
PSU Box

 

First Impressions:

The PSU comes in a very nice retail package and proudly boasts a 3 year warranty among other features.  This PSU features 80%+ Power Efficiency rating - meaning that if you're drawing 800W from the wall, the PSU is actually only providing a little better that 660W to your system.  This is something to keep in mind if you're using a Watt Meter on the input side of things.  Coming from Zalman we already expect this unit to be quiet, and this is due to a nice quiet 14cm fan as well as some heatpipes inside the unit.

 Inner Boxes
Inner Boxes
Wrong Country
Wrong Country

 

Inside the main box are a couple of smaller boxes.  The box on the top is larger and contains a well protected PSU.  The box on the bottom has is full of cables, including a fan connector that allows you to run system fans at either 12v or 5v.  They also include a power cable that apparently was made for a different country - continent rather, other than North America.  Hopefully this PSU works and detects input voltage, as there is no switch to select between 110v and 220v.


PSU First Look:

This PSU is a little longer than other standard ATX units and if you've got a really crammed case it may pose some problems.  The overall length is 21cm long, but it should fit in many mid-tower cases without issues.  If you have a top exhaust fan, measure before you purchase this unit.

 Attached Cables
Attached Cables
 Rear Grill
Rear Grill
   
 Fan Outside
Fan Outside
 Modular Connectors
Modular Connectors

 

The ZM850-HP has a very nice finish and looks very nice.  As you can see in the first picture above, this is not a completely modular unit at all.  In fact, if you've got a very basic system you won't even need to plug in any cables.  The cables that are hard-wired to the unit may be enough for some people.  If you are buying this unit though, and want as many as six 12v rails, you've probably got more gear.

The rear of the unit is well ventilated and you can see the heatpipe laden heatsinks through this wide open grill.  The entire unit is cooled by a very quiet 14cm fan that we clocked at 780rpm during heavy use.  This provides adequate cooling with virtually no noise - which is what we expected from Zalman.  On the inside end of the PSU you can see the different modular connectors as well as a switch.  This switch is actually a Standby Noise Filter Switch.  I'm not sure why Zalman wouldn't make the standby voltage "low noise" by default, but apparently there is a reason and you can enable or disable low electrical noise when in standby.

On the next page we'll take a look at PSU features and specifications.


Features & Specs:

Zalman is more known for its cooling products than for its Power Supplies, but with their products now reaching 850W, they are starting to get seriously noticed by the enthusiast community.  While they don't yet have the same reputation as Antec or Enermax, they are building a reputation that should take them into the cases of many computer gamers in the near future.  Below is a list of the features of this unit according to Zalman.

Dual Heatpipes Installed for Maximum Cooling Performance and Ultra-Quiet Operation
Dual heatpipes with ultra-high cooling performance incorporated on the main heat sources enable high load operation even at low fan RPM for a dramatic reduction in noise levels.

Improved Power Factor & Reduced Harmonics through Active PFC
By implementing Active PFC(Power Factor Correction), the Power Factor (PF) is improved up to 99% while harmful harmonic frequencies are reduced to meet the Line Harmonic Distortion Requirement of IEC61000-3-2 Class D Specification.

High Efficiency Design and 80 PLUS Certified
This power supply is capable of reaching a maximum of 86% efficiency (230VAC, Full & Typical Load) through its use of high switching frequency and low power-loss circuitry. This product has been certified with the 80 PLUS Power Supply Certification and guarantees a higher efficiency compared to uncertified products.
* 80 PLUS is an innovative, electric utility-funded incentive program that strives to integrate more energy efficient power supplies into desktop computers and servers.

ATX20+4 Pin Main Connector
ATX20+4 Pin Main Connector broadens the range of motherboard compatibility.

Supports ATX12V CPU 4-Pin and EPS12V CPU 8-Pin
Two ATX12V CPU 2 2 (4-Pin) power cables can be combined to form an EPS12V CPU 8-Pin power cable.

Four PCI Express VGA Power 6-Pin & 6+2 Pin Connectors
Four independent 6-Pin Power Connectors (two 6-pin & two 6+2 pin) provide support for Nvidia’s Quad SLI.

Module Cables
Modular cables provide organized cable management and improved air circulation inside the computer case.

Ultra Quiet 140mm Fan
The ultra quiet 2 ball-bearing 140mm fan maximizes the airflow and minimizes the noise level enabling a noiseless computing environment with optimized cooling.

Standby Noise Filter Switch
The 5Vsb Noise Filter eliminates high frequency noise in standby mode.
* The Standby Noise Filter Switch is NOT a power switch. The AC Power Cord MUST be unplugged in order to turn the power supply OFF.

Six Independent +12VDC Outputs
Six +12VDC rails supply power independently to the CPU, VGA, motherboard, and peripheral components for the highest level of stability and performance.

EZ Grip Connectors for ODDs & HDDs
EZ Grip Connectors for easy removal of the plugs from ODDs & HDDs.

Gold-Plated Terminals & 16AWG Wires
All connector terminals are gold-plated to minimize contact resistance and power lose.
16AWG (thicker than 18AWG) wires are incorporated to minimize voltage drop during high load operation.

Sleeved Cables
All power cables are sleeved for easy cable management and improved air circulation inside the computer case.

Multiple Safety Features
Over-Voltage Protection, Over-Current Protection, Short-Circuit Protection, Under-Voltage Protection, Over-Temperature Protection.

WEEE & RoHS
Complies with WEEE & RoHS environmental directives of the European Union.

 

Not only does this PSU have a decent list of features, according to the label, it has enough wattage to power almost every computer around.

Zalman Label
Zalman Label

 

More detailed information in the chart below.

Electrical & Physical Characteristics
AC Input Range
Voltage
100VAC ~ 240VAC ±10% DC Output
Frequency 47Hz~63Hz ZM850-HP
AC Input Current
(Rated)
115VAC 12A Output V. Output Load
ange
Combined
Power
230VAC 6.3A Imin Imax Ipeak
PFC Type Active PFC +3.3V 0.8A 25A 35A 191W 850W
Power Factor 99% Maximum
+5V 0.5A 30A 35A
Inrush Current
Limit (@ Cold start at 25°C)
115VAC 60A
+12V1 0.5A 18A 22A 768W
230VAC 100A +12V2 0.5A 18A 22A
Efficiency 86% Maximum @230VAC, Full&Typical load
+12V3 0.5A 28A 30A
DC Output
Voltage
Regulations
Output V. Regulation Range
At Full
Load
+12V4 0.5A 28A 30A
+3.3V ±5% +3.14V~+3.47V
+12V5 0.5A 18A 22A
+5V ±5% +4.75V~+5.25V +12V6 0.5A 18A 22A
+12V1 ±5% +11.4V~+12.6V -12V 0.0A 0.8A
27.1W
+12V2 ±5% +11.4V~+12.6V +5VSB
0.1A 3.5A 4A
+12V3 ±5% +11.4V~+12.6V Protection Features
+12V4 ±5% +11.4V~+12.6V Over Voltage Protection(OVP)
+12V5 ±5% +11.4V~+12.6V Over Current Protection(OCP)
+12V6 ±5% +11.4V~+12.6V Short Circuit Protection(SCP)
-12V ±10% -10.8V~-13V Over Temperature Protection(OTP)
+5VSB ±5% +4.75V~+5.25V Under Voltage Protection(UVP)
DC Output
Ripple
& Noise
Output V. Specification At Full
Load
Ambient Temperature
+3.3V 50mV Operation 0°C ~ +50°C
+5V 50mV Storage -20°C ~ +80°C
+12V1&2 120mV Ambient Humidily
+12V3&4 120mV Operation 5%RH ~ 95%RH
+12V5&6 120mV Storage 5%RH ~ 95%RH
-12V 120mV Dimensions
+5VSB 50mV 210(L) X 150(W) X 86(H) mm


If you were paying attention, you'll notice a discrepancy between the label on the PSU and the chart above.  According to the chart 12v3 and 12v4 are rated at 28A while 12v1, 12v2, 12v5 and 12v6 are rated at 18A.  The PSU states that each of the 6 +12v rails is 18A. 

We'll take a look at the cables and tear into this unit on the next page.


Modular Cables:

This is one of the more unique units I've seen as it has a lot of connected non-modular cables as well as a whole bunch of modular cables to boot.  The connected cables include the 20/24 Pin Motherboard Connector, 4/8 Pin CPU Power Connector, 3 SATA Connectors, 3 Standard Molex Connectors and two PCIe 6/8 pin connectors.  These are not modular - they are hardwired to the PSU.  The modular connectors include an additional 2 PCIe 6 pin connectors, 7 Standard Molex connectors, 9 more SATA Connectors, and 2 Floppy Connectors.  The diagram below shows all the cables and connections.  There are a bunch - 12 SATA, 10 HDD/ODD, 2 Floppy and 4 PCIe.

Cable Diagram
Cable Diagram

 

 

All of the cables are sleeved with a nice flexible material that helps maintain cable clutter while being co-operative enough to bend where you need it to go.  Below are a couple pictures of the different cable bundles.

 Molex Cables
Molex Cables
 SATA Cables
SATA Cables

 

Inside the PSU:

As we open this unit, please keep in mind that opening a Power Supply will completely void the warranty.  Not only that, but because of the large capacitors, you can suffer a serious electrical shock if you touch the wrong thing.  Please do not open your PSU to compare what the insides look like.  Instead, click on the images below for a closer look.

PSU Open
PSU Open
 Long Sinks
Long Sinks
   
 Heatpipes
Heatpipes
 14cm Fan
14cm Fan

 

The heatpipes appear to cool the unit quite well as it stayed quite cool during heavy testing and prolonged use.  We managed to pull a maximum of 683W through this unit during some Call of Duty 4 in SLI and it got quite warm, but remained quiet and appeared to be solid as the system didn't suffer any instability.

On the next page we'll briefly cover our PSU Test methods before we jump into full-blown PSU testing.


Test Setup & Info:

In the past, we've prided ourselves on real-world testing.  For graphics cards, CPUs and memory, what matters is what takes place in real applications and games.  We also held that philosophy for PSU testing, but after a while, we realized that there is more to a PSU that being able to run a machine stable over a few weeks or months.  In reality, if there is a lot of ripple, this can damage sensitive traces on your $700 graphics card or $1300 CPU.  A multi-meter alone is not good enough to check PSU voltage stability.  It's for this reason that we've updated our PSU testbed, and will continue to improve the detail and quality of our PSU reviews.  That being said, we will still be testing the PSU in a system and will be including stress tests from real components in the real world.

We recently purchased a Tektronics TDS2002 60MHz Dual Channel scope and it has already become invaluable around the shop here at BCCHardware headquarters.  I've used it to troubleshoot everything from PSU's to Radars, and we are using it today to check the stability of the Zalman ZM850-HP 850W PSU.

 

Test System:

 

9W Tests: 

We initially plugged the PSU into an EZ PSU Tester 3 in order to power it on for our "idle" measurements.  As noticed below, the voltage rails were fairly stable with no load, but these aren't necessarily indicative of overall load performance.  According to our Kill-a-Watt, the power draw was 9W.  We thought of throwing out the results, but thought it would be interesting to include and compare with other power supplies to see how they manage a non-load situation, and how much power the PSU itself will draw.

 3.3v at 9W
3.3v at 9W
 5v at 9W
5v at 9W
 12v1 at 9W
12v1 at 9W
     
 12v2 at 9W
12v2 at 9W
 12v3 at 9W
12v3 at 9W
 12v4 at 9W
12v4 at 9W

 

Although there are a total of 6 +12v rails, I've only included pictures from the first four.  The results are almost identical, and to save space, time and to save you from clicking on an extra couple of screenshots, I've left the +12v5 and +12v6 images out of the above picture set.

You can see in the images above the Zalman 850W PSU delivers a fairly clean signal with no load.  It has less ripple and noise that the 1000W Thermaltake ToughPower we recently reviewed.  That being said, there is a noticeable spike in noise just right of the center division.  No-load noise is still well within spec and sits around 30mv across the board.

350W Tests:

We ran 200W and 350W and 650W tests on this unit, but have left out a bunch of screenshots.  All of these readings will be recorded in a chart at the end of the review, but for now we'll take a closer look at the power signal when under a 350W load.  This test is done with the system running two instances of Folding @ Home.  This load should be quite representative of many mid-range computers when running full-load so we included some screenshots at this load.

 3.3v at 350W
3.3v at 350W
 5v at 350W
5v at 350W

 

At 350W the system and PSU ran very solid.  According to our scope, the unit is within specs, but is much more "noisy" that the Thermaltake Toughpower at a similar load.  Everything was well within specifications but this trend could prove troubling as we get into higher load situations.

12v1 at 350W
12v1 at 350W

 

The Zalman PSU showed peak-to-peak ripple and noise in the mid-high 40mV range at 350W, while the Thermaltake Toughpower had a much better showing and stayed in the low 20mV to high 30mV range at a similar load.  The system powered by the Zalman 850W PSU is rock solid, but perhaps the smaller 18A rails are showing signs of weakness when every rail on this unit is being used - thanks to the dual PCIe power requirements of each 8800GTX graphics card.

On the last page we'll cover the 650W tests and see how this unit holds up when tortured with an overclocked Quad Core CPU and a pair of 8800GTX's that are running faster than 8800 Ultra's thanks to the Zalman Reserator XT.


650W Load Tests:

We've seen the Zalman PSU start off quite well with non-load and 200W load values, but things start to weaken as we run higher loads through this PSU.  It is rated for 850W, and while we can't run this at 100% load, we can still push it with a pretty powerful system in real world tests.  We record the results with a Tektronix TDS2002 scope, and this is how it shapes up under some pretty heavy testing.

 3.3v at 650W
3.3v at 650W
 5v at 650W
5v at 650W

 

Under a fairly heavy load the 3.3v line and the +5v line remain in the low 40mV range and are under the 50mV requirement - but not by a whole lot.  If this curve were to continue, we'd see results out of spec at 850W - if we could load up the PSU that heavily.  The reality is that many people who would draw 800W+ are going to buy a bigger PSU, but if it's rated at 850W, it should be able to perform within spec at the rated load.

As we jump into the 12v rails, we'll cover what each rail does as we go.

 12v1 at 650W
12v1 at 650W
12v2 at 650W
12v2 at 650W

 

As you can see above, things are getting more interesting. . . The +12v1 rail is the main motherboard 24 pin connector and is responsible for many of the system functions.  This rail is reporting at 86mV peak-to-peak values, and while it is within spec, it is still pretty whacky.  The +12v2 rail is used for the 4/8 pin CPU connector and is also showing signs of stress.  It is a bit lower at 78mV, but it is still quite noisy and shows a noticeable ripple.

+12v3 and +12v4 are for PCIe connectors 1 and 2 and are connected to separate 8800GTX graphics cards.  The results below have been taken during 3DMark06 at 2560x1600 with 8x AA and 16x AF.  These cards are overclocked and working pretty hard as you can see below.

 12v3 at 650W
12v3 at 650W
12v4 at 650W
12v4 at 650W

 

These rails are also showing signs of stress and have a much higher ripple and noise reading that the Thermaltake Toughpower with its heftier 12v rails.  The +12v3 rail is averaging 64mV peak-to-peak while the +12v4 rails measures 76mV peak-to-peak.

The +12v5 rail s shared between PCIe 3 and the ODD/HDD Molex connectors.  Remember there are a total of 10 ODD/HDD connectors as well as 2 Floppy connectors, so sharing this 18A rail with a graphics card is pretty risky.  If the rail had higher amperage, it would help, but if you had all twelve connectors used, as well as a graphics cards, you'd be in bad shape.

 12v5 at 650W
12v5 at 650W
12v6 at 650W
12v6 at 650W

 

The +12v6 rail is shared between the fourth PCIe connector as well as with the 12 SATA connectors.  My concerns are the same as with the shared Molex/PCIe connector, and the results above speak for themselves.  Overall, ripple and noise remained within spec, but the 12v5 rail was up to 70mV while the 12v6 line held at 64mV.  Not a very impressive showing, but within specification all around.

Below are the charts that show average voltage as well as average peak-to-peak ripple and noise.

Ave. Voltage

 

 Ave. Ripple

 

Conclusion:

The Zalman ZM850-HP PSU is currently the largest PSU from Zalman.  While it promises to be quiet, it is a bit weak for today's high-end systems and seems to struggle a bit when forced to run a fairly heavy load.  That being said, it was always within its rated specifications, but we saw fairly large variability at higher loads.  If the trend continued up to 800W+, we could expect to see some rails out of spec.

This PSU is not a write-off by any means though.  It kept our system running solid for days of full-load (650W) testing.  Never once did we have system instability or issues of any kind.  To top it off, it's quiet - super quiet.  With the fan spinning at less than 800rpm, it really adds no noise to your system and is a great choice in a high-end HTPC or any mid to high end system that requires near silent operation.

Pros:

  • Very quiet PSU
  • 14cm fan & heatpipes keep things cool
  • Lots, I mean lots of connectors
  • Stable under hefty load 

 

Cons:

  • Ripple of 12v lines is fairly high at medium load
  • Half-modular design


Because of the high ripple and noise at a 650W load, I can't award this unit a Top Pick, but it deserves to be looked at if you're building a system that requires a good PSU that is very quiet.  For the price though, I can't help but think there are better PSU's for the money.

BCCRating

I'd like to thank ZalmanUSA for sending over this unit for us to review.  It's been a good unit to test out some 8800GTX SLI on a large display and showcase our test rig at a gaming conference.  Please post your thoughts and comments regarding this review in our forum at the "Comments" link below.