Connected to our APC SmartUPS SC 620, the PSU was stable at loads up to 375 watts when powered by the mains but couldn’t switch to the UPS’s batteries even at 280 watts.
Cross-Load Voltage Stability
The +12V rail is just as stable as in many other PSUs without dedicated voltage regulation. This voltage deflects the most from the required level when there’s moderate load on the +12V rail and high load on the other rails.
The +12V voltage is not going to be more than 4% off in the typical load range, though.
The +5V voltage is very stable, being only 3% off when there’s very high load on the +5V and +3.3V rails.
The +3.3V rail is similar to the +12V one. Its voltage can be up to 4% off the required level at low loads.
The CTG-600-80P was unstable at zero load on the +5V rail (we had to set this voltage higher to avoid triggering the PSU’s protection) but the real picture of low loads this PSU can support is better than in our diagram. The fact is the PSU would lose the Power OK signal when the load was suddenly switched to the +12V rail as is typical of this test, although the voltages were all within the permissible limits. By increasing the minimum load on each rail we made the PSU stable for our test, but such sudden changes in load can hardly occur in real-life usage scenarios.
Output Voltage Ripple
The high-frequency voltage ripple is quite strong, the occasional spikes on the +12V rail even going beyond the permissible limits.
The same goes for the low-frequency ripple. It is within the required limits except for occasional spikes on the +12V rail.
Temperature and Noise
The PSU is cooled by a 7-blade 120mm Globe Fan S1202512L running on a sleeve bearing. This fan should be given credit for being the quietest among all in this review. It lacked any foreign noises that could be heard from the other fans from a close distance. However, the sleeve bearing is going to have a shorter service life than the ball bearings of the other PSUs’ fans.
The fan speed is no higher than 800 RPM until a load of 200 watts. The PSU remains noiseless at 1000 RPM and 250 watts thanks to the wire grid and high-quality fan. It is only at loads of 400 watts that the noise becomes annoying. The fan just can’t help producing a hiss of air flow at speeds above 1300 RPM.
The fan accelerates to 1700 RPM by the load of 500 watts and maintains that speed until full load.
The regulation algorithm is quite adequate but the fan might work at a lower speed considering the low temperature of the PSU at load.
Thus, the CTG-600-80P is almost silent at medium loads but becomes noisy at high ones.
Efficiency and Power Factor
At the reference loads of 20%, 50% and 100%, the CTG-600-80P was 86.1%, 87.1% and 83.2% efficient. Its peak efficiency of 87.6% was observed at 313 watts. That’s a very good result for a PSU that lacks any kind of official 80 PLUS certification.
The power factor is 98% at most loads, which is quite good, too.
There are no problems with the PSU’s standby source.
The Chieftec CTG-600-80P is an inexpensive product with good electrical properties. It is noisy at high loads and somewhat unstable at zero or suddenly changing loads.