Home device power use: Difference between revisions

From Helpful
Jump to navigation Jump to search
Line 4: Line 4:


<!--
<!--
tl;dr:
* laptops on the order of 40W in use, idling at maybe 10W with things dialed down


* assume a desktop on the order of 150W in use (more in gaming), idling at maybe 80W
: plus their monitor(s) on the order of 25W, more for larger and brighter
: with some specific choices you can push them down to 50W idle. Less is possible but gets harder.
:: Particularly if you want it to scale from beefy to nothing (those tiny-box computers may use 10-15W but will also never do anything quickly)
* laptops tend to be ahead in "scaling down power use when idle" because it has more direct implications (battery life)
: good for expectation management of how good you ''might'' get a desktop when you take specific care
:: (not ''all'' of them - certain gamer laptops were only designed to be ''portable'', not to be efficient)
: also suggests using a decent laptoo with a dock as your main computer may be a ''simpler'' solution.
-->
<!--
A desktop PC not designed with power saving in mind may idle around 70..100W.
A desktop PC not designed with power saving in mind may idle around 70..100W.


Line 11: Line 25:
: up to 400W on a gaming machine working hard
: up to 400W on a gaming machine working hard


 
'''Laptops''' tend to be ahead in  
 
'''Laptops''' tend to be ahead in "scaling down power use when idle",
: and can sit in the range of 20-40 Watts in regular use, down to maybe 10W idle
: and can sit in the range of 20-40 Watts in regular use, down to maybe 10W idle
: up to 150W when working very hard, maybe more if they are gaming laptops.
: up to 150W when working very hard, maybe more if they are gaming laptops.
: You can basically tell by the power adapter - if it's 60W, it's never going to draw that much.
: You can basically tell by the power adapter - if it's 60W, it's never going to draw that much.
Those tiny-box computers may use 10-15W - but will also be ''slow''. You're best off using them as thin clients.
A basic desktop .
: is hard to get to idle under 50W idle or so (not that they can't, but it's not a common requirement without also being a thin client sort of thing)
: will easily cross 100W when doing real work.
Beefier desktop may be 100W idle and hundreds when gaming hard.
-->
-->


<!--
<!--
'''Can we do better?'''
'''Can we do better?'''


Line 47: Line 40:
Some very informed choices can push a desktop down to 20W idle.     
Some very informed choices can push a desktop down to 20W idle.     


Note that the level that laptops are at are great for expectation management here about how much you can scale performance ''and'' power in one system - because laptops they have much more direct incentive to have lower idle power (to save battery) ''and'' also be fast enough under use.  
If you can accept 15..25W idle, your search becomes a little easier than if you wanted 5..10W


...which, yes, also means that if you want that, laptops ''are'' a nice low-power and potentially-scaling choice.  
It is no ''technical'' reason you can't have absolutely ''possible'' to have something that can draw 300W under load and 15W idle, but the ''practical'' amount of research to get that is... "so you wanted another hobby?" levels of work.
You might be one dock away from using it as your main PC with no plugging bother.






One of the main questions is how well the CPU can idle.


* if you can accept 15..25W idle, your search becomes a little easier than if you wanted 5..10W
In the past, CPUs focused more on the 'how ''fast'' can we go' end,
and it's more recent that they also started to think about idle power.  
We have decent-to-great choices now, but still have to choose them.
{{comment|(Side note: the CPU's TDP rating is largely meaningless - it indicates the amount of cooling you need at maximum use, which is a poor indicator of how much it uses at minimum use)}}


* It is no ''technical'' reason you can't have absolutely ''possible'' to have something that can draw 300W under load and 15W idle, but the ''practical'' amount of research to get that is insane... "if you needed another hobby" levels.
But also, it's not only ''having'' these deep sleep states, it's also ensuring that they are actually used.
 
Sure that's automatic, ''but'' every piece of hardware('s drivers) could prevent it from going to the deepest sleep states.
* certain gamer laptops were only designed to be ''portable'', not to be efficient
It may involve some trial and error to even find ''which'' device prevents that,  
 
 
 
One of the main questions is how well the CPU can idle.  
 
This did not use to be as much of a design concern as 'how ''fast'' can we go' (except in laptops),
and yet the recent handful of generations have started to think about idle power, and have some decent-to-great choices.
It still varies, though. {{comment|(Side note: the CPU's TDP rating is almost entirely meaningless - it indicates the amount of cooling you need at maximum use, which is a poor indicator of how much it uses at minimum use)}}


But also, it's not only ''having'' these deep sleep states, it's also ensuring that they are actually used.
Yes that's automatic, ''but'' every piece of hardware('s drivers) could prevent it from going to the deepest sleep states.
It may involve some trial and error to even find ''which'' device it is,
and some of it will be motherboard and ''may'' not be changeable.
And most motherboards are designed to get them out the door, not for optimal power savings)


This isn't something you can necessarily find in the spec sheets.  
And with bad luck that's motherboard stuff that isn't even changeable.
Most motherboards are designed to get them out the door, not for optimal power savings.
This isn't something you can necessarily find in the spec sheets either.  


If you want to avoid a complex search and some purchases,  
If you want to avoid a complex search and some purchases,  
Line 87: Line 72:


Any additional hardware may have its own ideas.  
Any additional hardware may have its own ideas.  
Say, if I have a server that idles at 10W and put in a GPU that idles at 30W, meh.
Say, if I have a server that idles at 10W and put in GPUs that idle at 20W, meh.
 
 
-->
-->


<!--
<!--
Note that ''standby'' almost necessarily still uses a few watts of power.
Note that ''standby'' almost necessarily still uses a few watts of power.
: This is largely because the DRAM has to be actively refreshed{{verify}}.
: This is largely because the DRAM has to be actively refreshed{{verify}}.
Line 109: Line 89:


<!--
<!--
The CPU's TDP is an indication of the maximum -- ''only''.  
The CPU's TDP is an indication of the maximum -- ''only''.  


Line 119: Line 97:




When going for power efficient
When going for power efficient, know that watts per job done doesn't vary a lot, so if you expect it to be busy (e.g. for certain kinds of servers) it's a relatively moot point.
know that watts per job done doesn't vary ''too'' much,
 
so for servers it's relatively moot{{verify}}.
And a a gamer PC during gaming will ''always'' be a power hog.
And a a gamer PC during gaming will ''always'' be a power hog.


For desktop and mobile it's not so much about what it can do working hard,
For desktop and mobile it's not so much about what it can do working hard,
and much more about how much it can scale down when relatively idle,
and much more about how much it can scale down when relatively idle, because that might be most of the time.
because that might be most of the time.




There are sometimes mild-looking variants where one CPU idles at dozens and another at a handful of Watts.


When looking for these, the C states are an indication of how deeply it's designed to sleep,
The deeper a CPU wants to sleep, the more than any installed hardware needs to support all that,
but it's a far-from-perfect indication.
 
That said, the deeper it wants to sleep, the more than any installed hardware needs to support all that,
which is why this is a bit of a specialization.
which is why this is a bit of a specialization.


In Intel there is a distinction between  
In Intel there is a distinction between  
Line 143: Line 115:




During the CPU C3 State, the CPU clock generator is turned off.
During the CPU C6 State, the power to all cache is turned off.


Core
''generally'', C3 is idle but ready to go, and a higher number is turning off even more things.
C3 - L1/L2 caches flushed, stops clocks
 
C4 - reduces voltage
 
C5 - disables cache, reduces voltage more
Core C state
C6  
: C3 - L1/L2 caches flushed, stops CPU clock
C7 - C6 and LLC may be flushed.
: C4 - reduces voltage
C8 - C7 and LLC must be flushed.
: C5 - disables cache, reduces voltage more
: C6  
: C7 - C6 and LLC may be flushed.
: C8 - C7 and LLC must be flushed.
 
Package C state
: C2 - all CPU cores in C6
: C3 - all CPU cores in C6, graphics in any state?
: C6 - Package C3 + BCLK is off + allows voltage reduction
: C8 - cores requested C8 + disables last level cache
: C10 - Package C8 + display in PSR or powered, all VRs at PS4 + crystal clock


Processor Graphic state
Processor Graphic state
RC0 (Graphics active state)  
: RC0 (Graphics active state)  
RC1
: RC1
RC6 (Graphics  
: RC6 (Graphics  
 
Package
C2 - all CPU cores in C6
C3 - all CPU cores in C6, graphics in any state?
C6 - Package C3 + BCLK is off + allows voltage reduction
C8 - cores requested C8 + disables last level cache
C10 - Package C8 + display in PSR or powered, all VRs at PS4 + crystal clock




Line 172: Line 145:
====GPU====
====GPU====
<!--
<!--
A powerful GPU working hard are probably the hungriest component you have, on par with powerful CPUs. 50 to 200W isn't crazy for a GPU.
A powerful GPU working hard is probably the hungriest component you have, on par with powerful CPUs. 50 to 200W isn't crazy for a GPU.
 


That said, a moderately powerful GPU might idle at 5 to 15W.  
That said, a moderately powerful GPU might idle at 5 to 15W.  
Which is pretty decent, but not ideal if you wanted a very power efficient system.
Which is pretty decent power scaling, but still not ideal if you wanted a very power efficient system.
-->
-->


Line 187: Line 159:


In standby they tend to still use a few watts.
In standby they tend to still use a few watts.


-->
-->
Line 198: Line 169:
Platter may take 4 to 10W while spinning (more while spinning up - assume it might be 20W)  
Platter may take 4 to 10W while spinning (more while spinning up - assume it might be 20W)  


SSD might be 3 to 5W for SSDs and NVMe in use - but this can be multiples higher for higher end.
SSD might be 3 to 5W for SSDs and NVMe in use (can be multiples higher for higher end), and can be negligible while idling.
 




Line 205: Line 175:
whereas SSD power use is more related to how much you use it (in particular write),
whereas SSD power use is more related to how much you use it (in particular write),
and can be quite low when idle.
and can be quite low when idle.
Note that SSD isn't much more efficient than platter in active use, but ''is'' when idle.




Line 230: Line 203:


<!--
<!--
Your component draw is, roughly:
* Idle draw is often around 70W when doing nothing or just browsing wikipedia
* Peak draw is often between 100W and 200W on most regular hardware
* When  adding fancier CPUs, and even vaguely capable GPUs, you can more easily look at 400W total




Line 241: Line 209:
: In part because you can't perfectly predict how much current will be drawn from the different voltage rails, so you need some leeway
: In part because you can't perfectly predict how much current will be drawn from the different voltage rails, so you need some leeway
: In part because you often can't tell the quality of the PSU, so you build in a margin
: In part because you often can't tell the quality of the PSU, so you build in a margin
And when estimating that peak, think 70W when poking at a browser, 100 to 200W in more active use, and maybe 300W to 400W while gaming.




Revision as of 10:41, 16 July 2023


Computers

CPU

GPU

Monitor

Storage

Motherboard

Power Supplies

Audio amplifier

Smaller devices

Heaters and coolers

Water cookers

Retrieved from "https://helpful.knobs-dials.com/index.php?title=Home_device_power_use&oldid=89695"