Sky Hawk GM670SC Power One Power Supply Review

Cases & PSU/Power Supplies by KeithSuppe @ 2005-12-02

Sky Hawk aka Eagle Technologies, has upped the ante on their GM-SC power supply series. The most powerful model in that series, the GM620SC specified Peak Power from 640W ~ 680W. Extrapolating from Sky Hawk?s Peak Power formula in theory the GM670SC will offer Peak Power between 690W ~ 730W. Let?s find out how it performs.

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Test Setup / Conclusion

Test Setup and Methodology

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I taxed the GM670Sc using multiple systems including an A64 3500+ on PCPartner's RS482MK9 (Radeon Xpress 200) mobo and a Pentium 630 running on Asus P5ND2-SLI Dlx (nVIDIA C19) running SLI. Additionally I placed multiple loads on just about every molex. Our goal is to prove the GM670SC worthy of its rating or push it till it leaps out of the case and cowers behind a PCPower&Cooling 850 SSI, the only other PSU I've connected this many ancillaries to. Both systems are water cooled with Alphacool hardware. The A64 will be water cooled via Alphacool's 12V CORA 662 XP passive radiator kit. The NexXxos XP (CPU cooler) for Socket-939. For our Socket-775 system we'll switch out the NexXxos XP CPU-waterblock for the CAPE KC42-X2 Pro Copper cooler, based on the same Cora 662 passive radiator powered by the Alphacool AP1510 Centrifugal 12V pump. Included with this pump is the Alphacool Voltage Module 12-24V AP the voltage controller can adjust pump pressure switching between 12V and 24V in 3V increments.

Pictured above, the A64 system, below the Pentium running SLI with dedicated H20 North Bridge cooling.

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Test Systems
CPU 1.) A64 3500
2.) Pentium 630 Retail (SL7Z9 3.0GHz 2MB L2 1.25V ~ 1.388Vcore) Socket-775
Mainboards 1.) PCPartner RS482MK9-A64S Radeon Xpress 200 chipset.
2.) Asus P5ND2-SLI Deluxe (BIOS 0605)
Memory 1.) GSKill DDR600/PC4800 512MB-kit CL2.5-4-4-8
2.) Crucial Ballistix Tracer BL2KIT6464AL664 PC2-5300/2x512MB 4-4-4-10
Graphics 1.) Gigabyte GVNX68T256DH (6800GT)
2.) Gigabyte GV-NX68T256DH x2 in SLI mode
Power Supply Sky Hawk PowerOne GM670SC
Cooling 1.) Alphacool 12V Cora 662 XP (passive H20-system). Water block NexXxos XP
2.) Alphacool Cora 662 (substituting CPU block CAPE KC42-X2).
2.a) C19 North Bridge (dedicated) H20 set - Alphacool AP 910 Centrifugal Pump, Radiator NexXxos Pro II, fans 2x Papst 4412 120mm, North Bridge cooler NBX-N (modified)
Operating System Windows XP SP3

Audio Standby and Achilles’ Heel

The mythological Achilles, a Trojan warrior was son of Thetis and Peleus. He suffered from a weakness brought about by his own mother who sought to make him immortal immersing him into the magical waters of the river Styx. Tragically she overlooked an important detail as she dipped him once failing to dip him a second time so she could transfer her grip from one ankle to the next. He became immortal save that one place on his ankle where his mother held him which was left un-touched by the magic waters and this became his weakness. Most reviewers have thought of Sky Hawk's Audio Standby feature as its Achilles Heel labeling it a marketing gimmick. Ironically I've found a use for the molex as its ideal for powering a pump keeping the "magic waters" of your H20 cooling system circulating continually. Below the cable is feeding the Alphacool voltage controller (small red LED on top).

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Sound Levels

Placing a microphone 1 cm from the PSU (at the point where the sound is greatest) I recorded PSU noise levels running IDLE and LOAD. The image below shows sound file comparison between the Sky hawk Power One GM670SC and PCPower&Cooling TurboCool 850 SSI. Each unit was recorded running under identical circumstances, in the system tested here today with the only variable being the Power Supply. System speeds, LOAD, temps, and room environment were identical. The reason for the large fluctuation in sound level between IDLE and LOAD on the GM670SC is due to its fans 40°C activation temp. Running Idle the fan remained still, while under Load the fan was active.

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(Click image for zoom) - (Click here to download MP3 soundclip)

Performance Tests

Rail voltages were tested "live" by inserting digital multimeter probes into the reverse side of the ATX connector, using the Radio Shack 22-813.

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Several methods were used to record voltages from the GM670SC, software included CPUCool which gave an indication of performance over time. The software's GUI includes a graph which can be run indefinitely with the display indicating any spikes or dips in voltages for 20-minute increments. Just about any formula can be run on the graph such temps, DISK activity, voltages, etc. To produce LOAD I used what I believe to be the most powerful CPU/FPU and VGA stress test utility S&M. Thumbnails are arranged in pairs from left to right representing IDLE then LOAD at a given frequency. Oddly CPUCool displayed CPU Frequency incorrectly in the Intel screenshots representing LOAD; however, S&M displays the correct speed.

AMD A64 3500 - PCPartner RS482MK9 - Gigabyte 6800GT

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Intel Pentium 630 - Asus P5ND2-SLI Deluxe - 2xGigabyte 6800GT (SLI)

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The charts below represent data from the multimeter. Additionally I used CPUCool to measure voltages and temps over time. CPUCool was used primarily for a record of tests. As a rule multimeter readings are more accurate then any software utility which I've used primarily for a testing record.

A64 - PCPartner RS482MK9-A64S H20 Cooled / Sky Hawk GM670SC

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Intel Pentium 630 - Asus P5ND2-SLI H20 Cooled / Sky Hawk GM670SC

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Pros :
+ Excellent Value
+ Solid Construction
+ Excellent Cooling
+ Modular cabling eliminates case clutter
+ Ample SATA connectors
+ Quality Molex (squeeze to disconnect)
+ Substitute use for the Audio Standby Molex as an ideal power source for a waterpump.
+ Silent at low case/ambient temperatures (<40°C)

- 12V rails very close to spec tolerances
- Absence of Potentiometers for rail voltages
- Could use a rear on/off switch.
- Eschew Audio Standby retain "hot" Molex

Sky Hawk Power One GM670SC impressed me for its diminutive size. It performed well; however, the 12V rails do concern me, especially since most CPU's draw their current from this source. Sky Hawk is well known for manufacturing quality products which belie their sticker price. I did have a few criticisms such as doing away with the Audio Standby feature perhaps investing the production cost into accessible potentiometers, a rear power switch, perhaps beefing up the internals. Still I believe the additional molex providing constant current should remain. In total this unit was able to power two OASE (Alphacool) pumps, Alphacool Voltage controller, 4 x 120mm fans, 90mm fan, two graphic cards in SLI, two SATA HDDs, two CD/DVD/RW drives, one SATA DVD-R/DVD-RW, Thermaltake water temp indicator, TTGI Digi-610 rheostat and a floppy drive. The PSU powered all these devices while overclocking the Pentium 630 from 3.0GHz to 4.0GHz without any problem. That's the best conclusion one could hope for. Highly Recommended.

Questions/Comments: forum thread
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