Test Methodology

Utilizing Extech's MiniTec MN26 digital Multimeter the positive probe was inserted into the ATX connector with the ground probe against the case. The photo above is simply for reference. Using this method each rail can be tested under IDLE and LOAD.

Intel Test System
CPU	Pentium 630 Retail (SL7Z9 3.0GHz 2MB L2 1.25V ~ 1.388Vcore) Socket-775
Mainboards	Asus P5ND2-SLI Deluxe (BIOS 0605)
Memory	Crucial Tracer Ballistix 5300 (2x512MB DC CL4-4-4-12)
Graphics	2 x Asus N6600GT (256MB GDDR3) SLI mode
Storage / Optical Drives	Maxtor Ultra 16 300GB S-ATA 150 Maxtor DiamondMax 120GB S-ATA Plextor DVD/RW SATA Hitachi GD-8000 DVD/ROM
Power Supply	PCPower&Cooling TurboCool 850 SSI Sky Hawk GM470PC / GM570PC
Cooling	Thermaltake Blue Orb II
Operating System	Windows XP
Case	Thermaltake Kandalf Aluminum Tower
Fan Compliment	(Case fans) Sunon 120MM 78CFM (front intake replacement), Hong Shen (Tt) 120mm 37CFM rear exhaust. Hong Shen (Tt) 90mm 27CFM rear exhaust.

Sound measurements

Sky Hawk states at their site the GM series is noiseless since the cooling remains off ( 0dBA) as long as the GM470PC / GM570PC internal temperature is less then <40°C, once the fan is running noise levels can reach a maximum of 30dBA according to their specs.

Using Intelli-Systems AR824 digital sound level meter at 150cm (approx 5ft) from source, the reading was 5dB to 7dB above ambient (42.3dBA) with the fan running. Just about every PSU I've tested recently has been eclipsed in noise by the front intake fan of the case I use, a Sunon 120mm fan which pushes close to 80CFM which doesn’t make it a silent fan.


Multi-meter Volt Readings vs. Asus PC Probe II

Software such as Asus PCProbe II and AI-Booster are only as accurate as the devices (thermistors) and formula (BIOS ver. etc.) written for those devices. Surprisingly Asus's monitoring software is highly accurate coming to within a few tenths of a volt on most readings. I've supplied a few screenshots below as an example of my testing method which involves taking a screenshot of the monitoring software just after recording the digital multimeter readout for each rail. The additional information will help determine the accuracy of the on-board monitoring devices and software (as long as the multimeter itself is accurate).

Voltages were recorded at Idle and under LOAD which was produced using the CPU/Memory system tester S&M. The screenshots below were taken at IDLE and then LOAD on the GM470PC running at default speed (3.0GHz) and default voltages (Vcore. DDR voltage etc.) in SLI mode.



Below we see S&M in the Power Supply stage which also runs the VGA overheat element in S&M. We see a drop on the GM470PC's 12V line from 11.90V to 11.84V which is within spec.



Finally our digital multimeter readings obtained by the method mentioned at the top of the page. In the chart below results for both power supplies are included measuring rails and Vcore running our 775-LGA Prescott 630 at 3.0GHz IDLE and 3.0GHz LOAD while the system was in SLI mode.




Conclusion

Sky Hawk's GM470PC/GM570PC are well organized and well constructed, if on the light side. Noise levels were not an issue insofar as being distracting, yet the fans remained on during 95% of the testing, undoubtedly the result of running in SLI mode. Taping a thermistor to the GM470PC's internal heatsink gave a reading of 51°C. For this reason I wouldn't recommend the GM470PC or GM570PC for a Dual Core overclocking rig, nor a high-end gaming SLI or Cross Fire rig.

While I was able to run the P5ND2-SLI in SLI mode cabling provided wouldn't provide for cards which require external power and any attempt at overclocking resulted in system crash. I chose a system which would take these units to the periphery of performance and did just that. Perhaps the best way I can summarize the "value" of Sky Hawk's GM470PC and GM570PC PSUs would be their price. At $52 and $62 these are for the entry level system, not an overclocking unit, nor a hardcore gaming rig. Four years ago these PSU's would be adequate for any type of system, today their entry level.

Pros
+ Compact, versatile, ergonomically friendly
+ Large 120mm self-regulating fan reasonably quiet.
+ Great price ( GM570PC $62 at MWAVE / GM470PC $52 at MWAVE)

Cons
- Rails slightly low.
- No potentiometers
- Crashed during overclocking in SLI mode.

Unfortunately CPUs such as those marketed by Intel have deflated the performance value of PSU's across the board. I knew things were getting completely out of hand when PCPower&Cooling introduced a 1kW PSU.

Questions/Comments: forum thread