Summary of measurement results
Modern switching power supplies should not have any problems with the flowing currents as they generate graphics cards. I couldn’t measure really sensationally high currents on any map or in any of the most diverse load situations. Spikes up to approx. There are 10 milliseconds, no question, because that is also in the nature of the matter, because demanding games also cause very different load changes.
However, it never even went beyond 40 amperes, which is surprising if you consider the scenario of the power supply manufacturer linked in the introduction. If you were to scale up to the nanosecond range, peaks up to 50 amperes are conceivable, but if then an OCP or OPP already triggers, the circuit is hushed and you don’t have to look for the blame with the graphics cards.
It’s no secret that AMD’s graphics cards switch at longer intervals than comparable Nvidia cards. But it is not so grossly rough again that there are exorbitantly high currents here for many milliseconds. This is exactly what Power Tune knows how to prevent very safely.
Correct power supply calculation
What I would advise, however, to make reserves back and forth, is an emotionless and in practice also clearly differentiated consideration of the possible power consumption or the flow of currents on the individual rails. Taking the pure TBP (Typical Board Power) as the basis for a power supply calculation would be plentiful blue-eyed and it suddenly becomes apparent why graphics card manufacturers often estimate significantly higher values. This is not a job creation measure for the power supply industry, but pure caution.
Without a really detailed review in this area, it is of course very difficult to estimate where the peaks are and how long the intervals of the peaks are at all. However, the inclusion of transients is essential for safe operation, because if the manufacturers of power supplies calculate one with a sharp pin, it is the expensive capacitors. In the following overview I have summarized again some values, which caught my eye in all the measurements:
Conclusion
The very short load peaks can be confidently set aside and one should really only think about values that are over one to two milliseconds. By the way, not only because of the possible shutdown of the power supply by a protective mechanism, but also because of the durability. The more hectic such a graphics accelerator sucks on the power supply, the faster the secondary capacitors get into the area of long-term care insurance. Whothen saves in the end is wrongly advised.
Of course, humbug is also something like 100% Japanese capacitors, because even the big Japanese now mostly manufacture in China. So you should first look at a really good power supply review, where the specifications of the secondary circuit are also discussed. Components make the difference, not any (beautiful) measurement curves. If then I would orientate myself to the “normal peak” presented here, maximum still at the maximum interval and hope that the manufacturer has packed reserves on its own.
Poor advice is who calculates narrowly on edge and hopes that it will somehow go well. So Pi times thumbs can actually never hurt 50 to 100 watt reserve. And maybe I’ll build a power supply calculator on the basis of all the measured values. time provided. And what is left for us as a conclusion from the whole story?
The short-term line recording of current graphics cards is in some cases significantly higher than the average values or what the chip manufacturers describe as Typical Board Power. These values are averages over a rather large interval. Depending on the quality of the secondary side of a power supply, the short load (1 to 10 ms) may be significantly higher.
I would therefore recommend that for power consumption areas of the graphics card between 150 and 200 watts TBP, the margin of the graphics card should be calculated by around 50 watts more and above that for high-end systems from approx. Just add 200 watts for safety and always 100 watts of reserve. This should cover the peculiarities of AMD and Nvidia cards well and you don’t have to spend hours on component control. Most reviews don’t give that away anyway.
As a conclusion of this test, I personally take with me the fact that in the future I will also give readers a power supply design recommendation in the future with my graphics card individual reviews. Without enthusing me as a servant of the power supply industry, but rather as the well-meaning neighbour, who might know better.
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