Antec VPF Series 650W PSU Review

Transient Response Tests

Advanced Transient Response Tests

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

In these tests, we monitored the response of the PSU in two different scenarios. First, a transient load (10A at +12V, 5A at 5V, 5A at 3.3V and 0.5A at 5VSB) was applied to the PSU for 200 milliseconds while the PSU was working at 20 percent load. In the second scenario, the PSU was hit by the same transient load while operating at 50 percent load. In both tests, we used our oscilloscope to measure the voltage drops caused by the transient load. The voltages should have remained 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 tests 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

VoltageBeforeAfterChangePass/Fail
12V12.086V11.986V0.83%Pass
5V5.077V4.962V2.27%Pass
3.3V3.381V3.189V5.68%Pass
5VSB5.059V5.006V1.05%Pass

Advanced Transient Response at 50 Percent

VoltageBeforeAfterChangePass/Fail
12V11.981V11.874V0.89%Pass
5V5.042V4.911V2.60%Pass
3.3V3.376V3.178V5.86%Pass
5VSB5.020V4.969V1.02%Pass

The +12V rail performed pretty well with transient loads, while the 5V and 5VSB rails encountered controlled voltage drops in our two scenarios. The weak spot was the 3.3V rail, which registered a huge deviation in both tests. However, it managed to keep its voltage within the ATX spec's specified range.

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

Transient Response At 20 Percent Load

Transient Response At 50 Percent Load

Turn-On Transient Tests

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

For the first measurement, we turned off the PSU, dialed in the maximum current the 5VSB could output and switched it back on. In the second test, we dialed the maximum load the +12V could handle and started the PSU while it was in standby mode. In the last test, while the PSU was completely switched off (we cut off the power or switched off the PSU by flipping its on/off switch), we dialed the maximum load the +12V rail could handle before switching on the PSU from the loader and restoring the 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 5.5V for 5V).    

We didn't notice any spikes or voltage overshoots here. The VPF650 performed very well in these tests. 

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  • iam2thecrowe
    I do like Antec PSU's, their range is very solid. Good write up. Good value PSU.
  • CTurbo
    I hope Delta is not going to get out of the consumer psu business completely. They've been one of my go-to oems for years. Top notch reliability.
  • Onus
    [Delta-built] Antec has been one of my go-to standards for years as well. Though it has been surpassed in efficiency, I may need to put my SG-650 in my will because of its anticipated durability.
  • 2Be_or_Not2Be
    When the author says "... Delta no longer has an interest in this market..." - what market is he talking about? I seem to recall that quite a few of my Dell servers had Delta OEM PSUs, and I think a number of Dell desktops had custom Delta PSUs as well. So is it only the consumer market that they don't want to supply anymore?
  • iam2thecrowe
    1396902 said:
    When the author says "... Delta no longer has an interest in this market..." - what market is he talking about? I seem to recall that quite a few of my Dell servers had Delta OEM PSUs, and I think a number of Dell desktops had custom Delta PSUs as well. So is it only the consumer market that they don't want to supply anymore?


    probably. There is now too much competition in the consumer psu market for it to be really profitable for some companies. It would make sense if a company only wanted to do anything other than generic PC ATX psu's, because they can charge a lot more for it.
  • Aris_Mp
    Yeap Delta is away from consumer market. They mostly make OEM PSUs now. As far as I know only Antec has a contract with them for desktop PSUs.