From: anton@mips.complang.tuwien.ac.at
scott@slp53.sl.home (Scott Lurndal) writes:
>Michael S writes:
>>On Wed, 24 Sep 2025 15:56:37 -0400
>>George Neuner wrote:
>>> 80+% of the power used by datacenters is devoted to cooling the
>>> computers - not to running them.
In the old times I heard that they used about as much power for
cooling as goes into the machines. In recent times, I have heard
about success stories where they use less.
says: "Most
air conditioners have a COP of 3.5 to 5", i.e., quite a bit less
energy is expended on cooling than is moved away.
>>> At the same time, most of the heat
>>> generated by typical systems is due to the RAM - not the CPU(s).
Where do you get this from?
>A typical 16GB dimm module will dissipate 3-5 watts. So 128GB will
>draw in the vincinity of 32 watts.
We have several machines with 128GB RAM. They idle at around 40W, and
a box with less RAM and otherwise the same hardware does not idle at
much lower power consumption. The RAM has no active cooler, no
passive cooler, and sits close to each other, so it cannot dissipate
lots of power, certainly not 32W.
By contrast, the CPUs on these machines have elaborate active cooling
solutions, and consume 105W TDP (142W power limit).
SSDs are also unlikely to be consuming a lot of power, given the kind
of cooling that they get. Yes, there are elaborate coolers for
M.2-format SSDs, but these is not the kind of format that the bigger
servers use (which rather use U.2 or U.3 SSDs), and even with M.2,
there is usually no need to use SSD cooling.
Maybe if you have a huge number of SSDs, power consumption may rival
that of the CPU.
- antn
--
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
Mitch Alsup,
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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