I'm curious about power consumption spikes for CPUs and GPUs. I've come across recommendations suggesting to increase your power supply wattage by 20% or even 40%, but they often lack solid backing. Is the Thermal Design Power (TDP) a reliable metric for understanding this, or does AMD's Adrenalin software's power limit slider actually push power consumption beyond what TDP indicates?
7 Answers
I've seen some recommend only a 20% buffer, which seems incredibly low. If my 4090 uses about 400W and the 5800x3D around 100W, we're close to 550W, suggesting a PSU of at least 650W at 20% extra, but that's risky. I got an 850W just to be safe for any spikes, especially since I'm undervolting for efficiency.
Fascinating stuff! For example, a 5090 can spike up to 900W for a millisecond and 630W for 10-20 milliseconds even when it's capped at a 600W power limit. This happens without violating any specifications.
Remember that a PSU's efficiency rating is typically based on a 50% load. So, if you're pushing things, that's an important detail to keep in mind as well.
Definitely, that's another aspect to watch out for!
It's best to target around 60% load on your PSU to stay efficient. For a setup like a 300W GPU plus a 120W CPU and other components, a 750W PSU would put you comfortably above that mark. Going for a cheaper PSU might save a bit upfront, but the efficiency loss can add up over time.
Looking at just TDP isn't sufficient. Different power supplies behave differently under load. For instance, I've had a Seasonic Prime Titanium 750W that would shut down under stress with my setup, while a Corsair RM750x worked fine. It's really hit or miss unless you're testing with precise equipment.
Thanks for the insight! It really sucks that there's no good resource for power consumption spikes.
To get accurate readings, consider picking up a Kill-A-Watt meter or check UPS systems that display power draw.
If you have access to the hardware, the best way to find out is to use a power meter. You can track the idle consumption and then see how much it spikes while gaming. For instance, an MSI 5070TI is rated for 300W but usually idles much lower and peaks when pushed hard. Stick with the manufacturer's recommendations for the PSU for best results, especially if you plan to overclock.
How did you get those numbers? Is it something in the product's spec sheet? I'm not sure where to find that info.