If Intel’s TDP figures aren’t actual power consumption figures, how do I go about sizing a PSU?
Experience. But it all depends. TDP gives a hint in some generations example epyc cpus TDP is relaivly acurate wheras the 35w tdp of intel second gen means litteraly anything between 10 and 60w.
But for consumer systems with an i or r5 cpu and a mid tier gpu 500w is enough. For a server without a gpu and similar cpu 300W will suffice.
dual socket systems of that cpu class maybe 400-500.
With more enterprise stuff 500-700 or with epyc maybe encroaching 1000w with some addin cards.
It depends on maany other variables like Drives attached, PCIe devices used etc.
The biggest unknown power consumers in my books are the motherboard and CPU. I’ve got figures for most everything else. I’m building a system around Sapphire Rapids. I hear they spike.
Honestly? Use Dell or HP’s research to your gain. Go hop on their site and configure something similar to your expected build. See what PSUs they offer and get something similar in scale. That will probably be overkill but you know it will work - they cannot have those servers crashing due to power.
I couldn’t find any useful info on the Dell configurator. HPE seemed to have something similar to what I want to make.
Tdp seems fine to me for psu sizing. At the end of the day the psu may have some overhead anyway. You may want to look at pcpartpicker. They provide an indication of psu capacity
I always add up all the power usage (ie cpu, video carde ect) then add 20-30%
How close do you want to get? Budgeting about 200W per socket for “normal”-ish CPUs and 400-450W per socket for latest EPYC should get you in the right range.
I’m on Sapphire Rapids.
In that case, just copy someone else’s homework. Look up what Supermicro is using for wattage in 1U non-GPU servers, and use those numbers.
A bigger one won’t use any more power than a smaller one and are generally more efficient. Platinum is more efficient than Gold, which in turn is more efficient than Bronze.
Graphics cards really suck up power. Allow for the number of disk drives to have too.