Geekzone: technology news, blogs, forums
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.

80 posts

Master Geek

Lifetime subscriber

#268143 2-Mar-2020 09:30
Send private message

I need to replace my PoE switch which has died.


My dilemma is really around active vs passive cooling - my general impression is that passive cooling products are usually overly optimistic and likely to die sooner than actively cooled systems.


I've got a unifi setup at home, so keen to stick with their line of products.


I'm comparing the passively cooled USW-24-POE Gen 2 vs the USW-Pro-24-POE Gen 2. For my needs, the difference is no fan vs fan (and to a lesser degree power output). I'm pretty sure that 120W from the home model would be enough for my needs, however 22.5 dB fan noise from the pro would be fine if it'll help keep the system cooler.


It needs to power:


  • 3x Unifi cameras
  • 2x UAP-AC-pro access points
  • 2x UAP-IW-HD access points
  • Yealink WP52 base station.

So, is anyone using the passively cooled USW-24-POE Gen 2? How hot does it get (ideally under a similar load), and what's the airflow like around your setup?


The pro has a max power output of 450w, vs 120w for the non-pro model. Is heat production likely to be the same if using the USW-Pro-24-POE Gen 2 for the same given load?


I'm leaning towards the pro model, but wonder if I'm over calling it.


The device will sit in a rack with approx 1" space above it (with a non-POE switch) and 2" below. The rack is in a cupboard which gets up to about 30-35 deg in summer. The cupboard door stays open to aid with airflow, and there's an extractor fan at the top of the cupboard to vent heat, but that fan is noisier than a jet engine so I'd prefer not to use it if I can avoid it.

Create new topic
23386 posts

Uber Geek


  #2430463 2-Mar-2020 21:14
Send private message

Fan noise is in dBr, so basically totally misleading numbers there.


You are also getting the 10 gig uplink on the pro which the other does not have, and the fancy screen which will look nice if you also get the dream machine pro to use as a router when that is available here finally.


560 posts

Ultimate Geek

  #2431520 2-Mar-2020 23:50
Send private message

I have never used a POE switch, but as a general rule, fans are the earliest thing to die in most equipment unless you oil them at least annually.  And not all fans can be oiled.  When a fan fails, it often means the equipment will overheat and die within seconds or minutes.  So fanless equipment, when properly designed and used with the specified ventilation room, is normally much longer lasting than equipment with a fan.  Not all fans are the same, though.  Big slowly rotating fans tend to last a long time, where small fast ones die early and are much louder also.  And the bearing type matters a great deal.  Ball bearings rule!


The rack mount form factor used in a lot of switches limits the size of the fans that can be used - they tend to be small noisy ones with low lifetime.  So it pays to check on the fan type and quality before buying equipment with fans.


As an example, I have had both fan and fanless Nvidia video cards.  All the fanless ones are still operational - they have lasted until they have had to be replaced for other reasons and would still work if installed again.  Typically I have used them for 8+ years 24/7.  One is still in use.  The one Nvidia card I tried with a (tiny) fan failed within a couple of years of 24/7 operation.


As a counter example, last year I retired my old 16 port gigabit switch in favour of a 24 port managed commercial grade switch.  It was a rack mount style one, and was cooled by three tiny fans on the right hand side.  They were quite noisy, and got a bit noisier over its lifetime, but they were all still running fine last time I powered it up.  So I presume that they were quality fans.  It had been running for 7+ years 24/7 at retirement.


80 posts

Master Geek

Lifetime subscriber

  #2431689 3-Mar-2020 11:27
Send private message

Thanks for the replies.


@fe31nz Thanks for the insight regarding fanless products - it's interesting to get a counter opinion and I understand the concept that no moving parts means less mechanical reason to break. I'm unsure how applicable experience with a fanless graphics card is in this situation however, as those systems invariably still have a system fan to move air past the heat sink, and usually aren't as cramped as a 1 unit server.


This will be my third rackmount PoE switch. I presume that it was heat that killed my first two. I've never had a fan fail, although do take care to ensure they're working properly and perform basic maintenance like making sure they don't get clogged up with dust. Fan quality and airflow design both matter, both from air movement and noise perspective. In systems I've built previously I tend to use large noctua fans for that reason. While I can replace the fans with higher quality ones in the switch (voiding the warranty), I can't change them for something larger.


The early Unifi POE switches were really hot and noisy. They have been progressively improving since that time, I'm just not sure if they've improved enough to warrant no fan in the location where my rack is situated.


So taking advice from @richms I'll try out the pro model. I've started getting some 10G gear so I'll consider it future proofing.

4196 posts

Uber Geek


  #2432142 3-Mar-2020 21:39
Send private message

Have you considered other brands PoE switches? have a good variety and pricing is very good. For same price as Ubiquiti 24 port USW-Pro you can get 48 port version of variant.



Do whatever you want to do man.


Create new topic

Twitter and LinkedIn »

Follow us to receive Twitter updates when new discussions are posted in our forums:

Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:

Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:

News »

National Institute for Health Innovation develops treatment app for gambling
Posted 6-Jul-2020 16:25

Nokia 2.3 to be available in New Zealand
Posted 6-Jul-2020 12:30

Menulog change colours as parent company merges with Dutch food delivery service
Posted 2-Jul-2020 07:53

Techweek2020 goes digital to make it easier for Kiwis to connect and learn
Posted 2-Jul-2020 07:48

Catalyst Cloud launches new Solutions Hub to support their kiwi Partners and Customers
Posted 2-Jul-2020 07:44

Microsoft to help New Zealand job seekers acquire new digital skills needed for the COVID-19 economy
Posted 2-Jul-2020 07:41

Hewlett Packard Enterprise introduces new HPE GreenLake cloud services
Posted 24-Jun-2020 08:07

New cloud data protection services from Hewlett Packard Enterprise
Posted 24-Jun-2020 07:58

Hewlett Packard Enterprise unveils HPE Ezmeral, new software portfolio and brand
Posted 24-Jun-2020 07:10

Apple reveals new developer technologies to foster the next generation of apps
Posted 23-Jun-2020 15:30

Poly introduces solutions for Microsoft Teams Rooms
Posted 23-Jun-2020 15:14

Lenovo launches new ThinkPad P Series mobile workstations
Posted 23-Jun-2020 09:17

Lenovo brings Linux certification to ThinkPad and ThinkStation Workstation portfolio
Posted 23-Jun-2020 08:56

Apple introduces new features for iPhone iOS14 and iPadOS 14
Posted 23-Jun-2020 08:28

Apple announces Mac transition to Apple silicon
Posted 23-Jun-2020 08:18

Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.