EVGA 450 B3 PSU Review

Transient Response Tests

Advanced Transient Response Tests

For details on our transient response testing, please click here.

Ιn these tests, we monitor the 450 B3's response in several scenarios. First, a transient load (10A at +12V, 5A at 5V, 5A at 3.3V, and 0.5A at 5VSB) is applied for 200ms as the PSU works at 20 percent load. In the second scenario, it's hit by the same transient load while operating at 50 percent load.

In the next sets of tests, we increase the transient load on the major rails with a new configuration: 15A at +12V, 6A at 5V, 6A at 3.3V, and 0.5A at 5VSB. We also increase the load-changing repetition rate from 5 Hz (200ms) to 50 Hz (20ms). Again, this runs with the PSU operating at 20 and 50 percent load.

The last tests are even tougher. Although we keep the same loads, the load-changing repetition rate rises to 1 KHz (1ms).

In all of the tests, we use an oscilloscope to measure the voltage drops caused by the transient load. The voltages should remain within the ATX specification's regulation limits.

These tests are crucial because they simulate the transient loads a PSU is likely to handle (such as booting a RAID array or an instant 100 percent load of CPU/GPUs). We call these "Advanced Transient Response Tests," and they are designed to be very tough to master, especially for a PSU with a capacity of less than 500W.  

Advanced Transient Response at 20 Percent – 200ms

VoltageBeforeAfterChangePass/Fail
12V12.190V12.040V1.23%Pass
5V5.034V4.902V2.62%Pass
3.3V3.314V3.163V4.56%Pass
5VSB5.082V5.028V1.06%Pass

Advanced Transient Response at 20 Percent – 20ms

VoltageBeforeAfterChangePass/Fail
12V12.188V11.977V1.73%Pass
5V5.034V4.885V2.96%Pass
3.3V3.314V3.159V4.68%Pass
5VSB5.082V5.044V0.75%Pass

Advanced Transient Response at 20 Percent – 1ms

VoltageBeforeAfterChangePass/Fail
12V12.189V11.969V1.80%Pass
5V5.034V4.886V2.94%Pass
3.3V3.314V3.160V4.65%Pass
5VSB5.082V5.036V0.91%Pass

Advanced Transient Response at 50 Percent – 200ms

VoltageBeforeAfterChangePass/Fail
12V12.172V12.028V1.18%Pass
5V5.021V4.896V2.49%Pass
3.3V3.302V3.157V4.39%Pass
5VSB5.038V4.984V1.07%Pass

Advanced Transient Response at 50 Percent – 20ms

VoltageBeforeAfterChangePass/Fail
12V12.172V11.966V1.69%Pass
5V5.021V4.863V3.15%Pass
3.3V3.301V3.135V5.03%Fail
5VSB5.038V4.996V0.83%Pass

Advanced Transient Response at 50 Percent – 1ms

VoltageBeforeAfterChangePass/Fail
12V12.172V11.951V1.82%Pass
5V5.021V4.888V2.65%Pass
3.3V3.301V3.155V4.42%Pass
5VSB5.038V4.979V1.17%Pass

The +12V rail's transient response is good given this unit's low capacity. The 5V and 5VSB rails perform well enough, though the 3.3V rail encounters major deviations that lead to a failure in one of our testing scenarios.

Here are the oscilloscope screenshots we took during Advanced Transient Response Testing:

Transient Response At 20 Percent Load – 200ms

Transient Response At 20 Percent Load – 20ms

Transient Response At 20 Percent Load – 1ms

Transient Response At 50 Percent Load – 200ms

Transient Response At 50 Percent Load – 20ms

Transient Response At 50 Percent Load – 1ms

Turn-On Transient Tests

In the next set of tests, we measured the 450 B3's response in simpler transient load scenarios—during its power-on phase.

For our first measurement, we turned the 450 B3 off, dialed in the maximum current the 5VSB rail could output, and switched the PSU back on. In the second test, we dialed the maximum load the +12V rail could handle and started the 450W supply while it was in standby mode. In the last test, while the PSU was completely switched off (we cut off the power or switched the PSU off), we dialed the maximum load the +12V rail could handle before switching it back on from the loader and restoring power. The ATX specification states that recorded spikes on all rails should not exceed 10 percent of their nominal values (+10 percent for 12V is 13.2V, and 5.5 V for 5V).    

Perfect results here.

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  • raotor
    Blowing up on the bench & the fuse not blowing seems to me to be rather more than an issue. I'd like Tom's to go buy another retail 450 Watt unit & see if it does the same. In addition, I see no mention of the other units in the range being tested which is odd as all models within the B3 line were purchased. Do we know if, say, the 550 Watt version suffers from the same safety issue.

    Further, EVGA's lack of response to this fault is not good for their PR. I'd even go so far as to suggest that such a dangerous failing should be grounds for banning this model from sale until EVGA can recall & fix the units.
  • termathor
    Hi there,

    Curious if EVGA came back to you, guys @ Toms Hardware on this on this fuse not working ...
    Seems to me the issue was serious enough to warrant an investigation !

    Did they really not come back with an explanation ????