Question CPU power consumption under minimal load

[MeltedIron00]

95% of time my PC is pretty much idling (max I am doing is watching some youtube videos, or twitch streams).
HWMonitor shows that GPU uses around 7 Watts (what seems fine to me), but CPU 22 Watts, so I decided to look what can be done to lower CPU power consumption.

I tried to underclock and undervolt my Ryzen 5 5600, but I can't lower min power consumption.
Underclock and undervolt helps lower power consumption only when CPU is under load.

Is it even possible to run Ryzen 5 5600 sub 15 Watts when PC is at minimal load (0-3%)? 22 watts seems way too much when under full load is from (45-78 watts).

 

[CelicaGT]

If you are doing anything, such as watching video then your system is not idle. Undervolting at low clock speeds can cause random crashing. At true idle your CPU should typically be at around 10 W to 12 W (2 W CPU cores, 10 to 11 W SoC).

 

[MeltedIron00]

I understand. Question was about "minimal load" where CPU usage is 0-3%.

Even if I will close everything (except HWMonitor) and task manager/performance shows 0-1% CPU usage, CPU will use same 22 watts. Clocks and voltage is down, but power consumption is same 22 watts.
I assume wattage will drop in short time after HWMonitor will be closed, but this topic is not about it (not about idle).

 

[hotaru.hino]

Ryzen CPUs have higher idle power consumption because they have an I/O die in them. That represents a fixed power consumption because it's the hub for basically every major interface in the computer and you can't really lower clock speeds without a significant amount of delay to get things ramped up again. This is also on top of the I/O die being manufactured one process node higher than the CPU dies, so it'll consume more power by default.

The only way to further reduce power here is to reduce the performance of the interfaces. That means things like lowering the RAM speed and capping the PCIe version to say 2.0.

 

[Misgar]

What you need is a NUC (although probably not Intel because they're getting out of the market).

If I'm reading this Reddit thread correctly, the lowest powered NUCs consume less than 5W when idle, for the whole computer.
https://www.reddit.com/r/intelnuc/comments/dyu358/nuc_with_the_lowest_power_consumption_when_idle/

I'm running an old Fujitsu Futro 900 as a pfSense firewall and it draws less than 20W from the mains when performing its normal duties.

The 5600 is not a low power chip and together with the motherboard, SSD and peripherals, it's always going to draw more power than a small form factor micro computer.

 

[TerryLaze]

What you need is a NUC (although probably not Intel because they're getting out of the market).

Not even, a android TV box is enough to watch youtube, I don't know about twitch but I would guess it's the same.
Of course if he can afford a NUC/miniPC it would be great but they are pretty expensive just to watch videos with.

 

[MeltedIron00]

I never paid attention to power consumption and I always thought that CPU power consumption is very low at minimal load (sub 10 watts like GPU has 7 watts), but turns out I was wrong.

It's not that critical for me to change CPU/PC. I just wanted to know if there is any way to lower power consumption. If not then I will not keep my PC on 24/7, like I am used to over last 10 years.

 

[USAFRet]

Be careful about chasing minuscule benefits.

I don't know how much elec costs in your area, but for me, $0.12/kWh


So, lets calculate.... ( https://www.rapidtables.com/calc/electric/electricity-calculator.html )
Lets assume the system currently consumes 30 watts at "idle".
Running 24/7, that is $31.55 per year

Now, lets reduce that full system use by 1/3...down to 20 watts, running 24/7
Annual cost, $21.


Congrats, you've saved $10.55 per year.
Less than $1 per month.

The cost of 2x coffee shop coffees, per year.
Yes, every little bit helps. But the PC is nowhere near the big power consumer in the house.

 

[hotaru.hino]

After some tweaking, I managed to drop my 5600X's idle power consumption from about 25W to 15W, if we were to use HWiNFO as the source of information. Total system power consumption went down to 40-50W from the wall (so something like 25-30W with efficiency accounted for) if I was willing to take out my sound card. Otherwise that adds another 8-10W.

But also this means the system is going to be running at significantly reduced performance.

 

[MeltedIron00]

Congrats, you've saved $10.55 per year.
Less than $1 per month.

The cost of 2x coffee shop coffees, per year.
Yes, every little bit helps. But the PC is nowhere near the big power consumer in the house.

In my case should be around 1kWh (per PC) in a day x 2 PC = 2kWh * 356 = 712 in a year = ~130 euro.
10 watts = around 30 euro. Yeah, you are right, it's not that much.

It's just strange to see max 42 watts in games at 100% load and 22 watts at 1% load.

 

[hotaru.hino]

It's just strange to see max 42 watts in games at 100% load and 22 watts at 1% load.

Games aren't actually CPU heavy in the sense they're not multicore beasts. Most games still run 2-3 main threads that do a bulk of the work. As such, only 2-3 cores need to actually be running.

The idle power thing I explained earlier.