When the power supply suddenly switches off: Load peaks of graphics card and CPU measured together and counter-tested with power supplies | Basics & Practice

1 - Introduction and Technical Background 2 - GeForce RTX 3070 without and with OC - Gaming 3 - GeForce RTX 3070 without and with OC - Torture (Max. Load) 4 - Radeon RX 6800 without and with OC - Gaming 5 - Radeon RX 6800 without and with OC - Torture (Max. Load) 6 - Radeon RX 6800XT without and with OC - Gaming 7 - Radeon RX 6800XT without and with OC - Torture (Max. Load) 8 - Summary and Conclusion

CPU load peaks should not be underestimated!

The Ryzen 9 5900X is a 105-watt CPU, according to AMD. In the gaming loop, even this is clearly undercut and you are on average and without overclocking at a measurable 70 to 74 watts (RTX 3070), at 60 watts (RX 6800XT) or far below (RX 6800), depending on the GPU used. But these values are extremely deceptive, because with a conventional measurement one simply does not get further. Even measurement intervals with 100 ms are no real help here, because the devil is in the details.

In addition to that, the CPU load peaks can still soar to over 200 watts even in the 20 ms window (205 watts, RX 6800XT OC). This is a real big number, which must also be included in the power supply dimensioning! Even without overclocking, it’s still over 200 watts with the Radeon RX 6800, which is still relevant for any OCP/OPP, but only random and sporadic. But are there!

The sum of the load peaks from GPU and CPU can be fatal for the power supply unit

So far, I’ve always looked at the GPU alone, but that’s deceptive in many ways. The coincidence that two absolutely extreme spikes coincide is statistically not so frequent, but even what I could measure of coincidence of higher spikes over the longer measurement periods is enough to bring some PSU to its knees. Even if the Straight Power 11 550 Watt Platinum cut quite a good figure in the beginning, at the latest with a Radeon 6800XT it’s actually the end.

You also have to remember that power supplies age and manufacturers like to add 10 to 20% more power for safety reasons if they are anything to go by. But there is no guarantee. No one’s. Especially not over a period of years and a prolonged, very demanding assignment. Besides, we mustn’t forget that on top of the 12 volt rails, there’s about 25 watts extra for the motherboard and all that stuff, and with the total power consumption including 5 and 3.3 volts, there’s another 20 watts. this approx. 45 Watt surcharge on my measurement results of GPU and CPU are always to be planned in!

Conclusion and summary

What have we learned from this? Even in the middle class you should plan with 600, better 650 watts and more for the power supply and also buy good products. Reaching for the absolute cheap shelf will be bitterly avenged. Processors also generate extreme spikes in some places, and depending on the model and motherboard, this quickly becomes a trap for the power supply. I don’t want to advise against Asus motherboards in general, but the accumulation of problems that have occurred, also in the community, is definitely reason to think more carefully. By the way, also and even more so for the manufacturer who would like to be ahead in OC, but drags a spiky trail behind him like a fat hedgehog skin. It doesn’t really have to be, because it can be done without.

Today’s digression also shows that the discussion about single or multi-rail power supplies is actually idle, as long as the products have been planned and configured for their intended purpose. However, the manufacturers will not be able to avoid also designing and securing the EPS a little more generously, because this is often the crux of the matter. However, this can affect anyone, including single-rail PSUs, if the secondary capacitors are leached by both GPU and CPU.