Zalman 850W Heatpipe Cooled PSU - Test Setup, Methods and Testing

Article Index
Zalman 850W Heatpipe Cooled PSU
ZM850-HP Features and Specs
ZM850-HP Cables and Inside
Test Setup, Methods and Testing
650W Load Test and Final Thoughts

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.