CWWK i3-N305 Benchmarks & Power Consumption

As previously admitted I have a bit of an obsession with mini-ITX / SBC (single board computers). I love the concept of getting maximum performance in a small form factor, preferably using as little power as possible and as near silent as possible.

Depending where you live in the world today, electricity is becoming a relatively expensive commodity. Below is a graph showing UK energy prices relative to inflation.

As I write this, in the UK, average electricity cost is around £0.24 ($0.31) /kWh. Now if we think about a home server, powered up 24/7, we can quickly calculate energy costs based on average power consumption:

You can see that when you’re running a server 24/7, electricity cost over a 5 year life are significant, even if the power consumption is pretty low. So every time I see someone talking about using their 10-year old desktop PC as a Plex server I’m pretty sure they haven’t done their sums … chances are that it doesn’t make sense to reuse old, inefficient hardware when you figure in the power consumption. Even in the US where power is (generally) a bit cheaper it probably still pays to use something newer and more efficient.

Anyway, as a baseline, currently my main home server is this bad boy, the CWWK crazy, which has an Intel N100 4-core processor. It has 32Gb RAM, a 4Tb NVMe drive, 4Tb SATA SSD and a Coral dual TPU in the PCIe slot:

Baseline power consumption measured at the wall when powered on but idle is 11W. While running a bunch of containers and Frigate NVR with detection on 6 IP cameras it’s around 17W. That gives an annual electricity cost around £36, which for me is reasonable compared to paying a subscription for a cloud provider for smart cameras, with the added benefit of not streaming cameras inside my house to some random Chinese cloud…

Stopping all my containers and running a quick 7Zip benchmark gives me a sustained power draw around 23W for around 15 GIPS performance (about 1.5 W/GIPS) . On this PC I’ve increased the power limit to get increased sustained max performance (I’ve also added a fan).

So that’s my starting point of reference, let’s build out the CWWK N305 NAS board and see how it compares!

Here I’ve added 32Gb RAM and a 2Tb NVMe drive to the board. I’ve also added a Coral TPU to the second M.2 slot (which I believe is shared with the PCIe slot, so it’s an either-or). The system is powered using a PicoPSU and external 12V brick.

With Proxmox bare install and nothing running, this setup idles around 13.5W. That’s a bit more than the N100 build, but it’s giving me 4 extra cores to play with, roughly twice the performance headroom.

Hitting the system with a quick 7Zip benchmark we see a peak power consumption around 50W that settles after a few seconds to around 34W.

The benchmark figures show the same, a high initial peak around 28 GIPS then a lower sustained output around 13.5 GIPS. At peak performance that’s about 1.8W/GIPS, then throttled around 2.5W/GIPS

I tried to increase the power limit, but unfortunately it doesn’t seem to be possible on this processor / motherboard:

root@prox-n305:~# powercap-set -p intel-rapl -z 0 -c 0 -l 50000000
Error setting constraint power limit: No data available
Considerations for common errors:
- Ensure that the control type exists, which may require loading a kernel module
- Ensure that you run with administrative (super-user) privileges
- Enabling/disabling a control type is an optional feature not supported by all control types
- Resetting a zone energy counter is an optional powercap feature not supported by all control types

root@prox-n305:~# cat /sys/class/powercap/intel-rapl/intel-rapl:0/enabled
0

It’s possible there is a BIOS setting that can enable changing this …. I’ll dig in at a later date.

So the numbers are clear, we’re actually getting more bang/buck from the N100 in terms of performance vs power draw, with this hardware.

N100 ~ 1.5W/GIPS
N305 ~ 1.8-2.5W/GIPS

The flip side of course is that the peak performance of the N305 is roughly twice that of the N100, so for peaky workloads you have much more grunt available. Idle power load is comparable, but still better for the N100.