Benchmarking Pihole : Pi Zero vs Pi 3b+

Here's a benchmark comparing pi-hole running on a Pi Zero (with USB ethernet) vs a Pi 3b+.

tl;dr There was negligible performance difference for blocked domains, but a measurable difference in mean for forwarded + cacheable domains. Although the Pi 3b+ has a 11ms better mean response time for forwarded queries, the P95 for pi zero is better in both blocked and forwarded queries.

I would recommend using the Pi Zero.


Prior to the experiment, I assumed that the pi zero would be 30-50% slower in all cases, and that stddev would be larger (worse & more erratic latencies).

Hardware & Setup

Router: TP Link Archer C9
PI 3b+ : connected via 100mb ethernet into router, 32gb sandisk microsd card. Raspbian Desktop
Pi Zero-W : connected via usb ethernet adapter, 100mb ethernet into router, 8gb class-4 sd card. Raspbian Lite


I used dnstrace -- a go dns benchmark.
The client was a macbook pro connected via wifi.
Each test did 1000 queries with 10 concurrency ( go run dnstrace.go -c 10 -s -n 100 )


full histogram and results can be found here


pi 3b+

 min:		 16.252928ms
	 mean:		 38.372412ms
	 [+/-sd]:	 23.097544ms
	 max:		 385.875967ms

pi zero

DNS timings, 1000 datapoints
	 min:		 19.922944ms
	 mean:		 40.043544ms
	 [+/-sd]:	 7.762346ms
	 max:		 71.303167ms


pi 3b+

DNS timings, 997 datapoints
	 min:		 13.1072ms
	 mean:		 19.527493ms
	 [+/-sd]:	 12.101107ms
	 max:		 142.606335ms

pi zero

DNS timings, 999 datapoints
	 min:		 16.252928ms
	 mean:		 30.097752ms
	 [+/-sd]:	 5.005948ms
	 max:		 88.080383ms

Summary and Findings

I believe the zero is an adequate replacement for the pi 3b+ . Moreover, I was impressed and shocked that stddev on the pi zero was lower than the 3b+. So despite having worse mean forwarding response times, the P95 for pi zero is better in both blocked and forwarded queries.

:star: I'll leave these two devices online for a bit let me know if you'd like any further testing done. :star:


I've added benchmarks from a wired client to the gist results. The findings above are from the original wireless client.

i am quite interested in your 100gb ethernet. And surprise TP link router would support 100gb link. :open_mouth:

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haha me too i've fixed that typo :smiley:

I may not understand your test. A blocked domain should return from Pi-Hole in 1-2 msec at most. But you show means of 38 and 40 msec, with mins of 16 and 19 msec.

What is the time shown if you run dig | grep Query

$ dig @pihole3bplus.local | grep Query
;; Query time: 2 msec
$ dig @piholezero.local | grep Query
;; Query time: 3 msec

These individual responses are very fast. The results above are benchmarks to simulate bulk traffic (1000 queries x 10 concurrent)

Also, dnstrace seems to count network roundtrip, and I believe dig query time is not

I agree. When I run the same dig from my Mac terminal (wireless to the router, then to the switch and to the wired 3B+), it's 33-40 msec.

You may be testing your network more than either of the Pi-Holes. When I run this dig from the Mac to any of my Pi-Holes (3B+ wired or Zero W wireless), the query times are very similar. Within a msec. Averaging about 40 msec from the Mac, and 1 msec from the Pi, so that's 39 msec of network latency to any of them.

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Good point. I've added 4 more results taken from a WIRED client to the results gists. In that case servers and clients are all wired ethernet. The client was another pi zero

results GIST

And what do you conclude from this new data?

Overall still very impressed with the pi zero--would definitely recommend it. The wired results are a bit more as I would have expected -- the mean times for the 3b+ are all better. But the pihole stddev is very good which keeps it competitive.

How about you?

I have noticed no difference in DNS resolution speed between a wired 3B+ and a wireless Zero W in everyday use with a variety of client devices. So, from a purely Pi-Hole perspective, they run equally well and the platform difference is transparent to the user.

However, when you ssh into them, the 3B+ is significantly more responsive. Updates happen more quickly, rebuilding gravity (which you would never notice anyway, since it's done early Sunday morning normally), querying logs or databases.

A Zero W is plenty for Pi-Hole and at a fraction of the cost of a 3B+, a good choice.

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