# Recommended Heat Sink(s) and/or Fan(s)

**URL:** https://forums.sifive.com/t/recommended-heat-sink-s-and-or-fan-s/4430
**Category:** HiFive Unmatched
**Created:** [February 5, 2021, 1:52pm UTC](https://forums.sifive.com/t/recommended-heat-sink-s-and-or-fan-s/4430 "2021-02-05T13:52:10Z")
**Posts on this page:** 1
**Showing post:** 27

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### Author: ![sirn](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.sifive.com/sirn/32/1297_2.png) [@sirn](https://forums.sifive.com/u/sirn)
#### Post date: [June 20, 2021, 10:33am UTC](https://forums.sifive.com/t/recommended-heat-sink-s-and-or-fan-s/4430/27 "2021-06-20T10:33:29Z")

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Yes. See also [my previous post](https://forums.sifive.com/t/anyone-receive-their-unmatched/4421/59) 🙂

My HiFive Unmatched is using the 40mm to 25mm fan adapter with a 40mm Noctua and 120mm chassis intake fan. It’s sitting silently at 36.8°C MB/46°C CPU after 4 days of package(s) compilation at 25°C room temperature and 60% humidity.

The 40mm Noctua fan alone does not have enough CFM to cool the CPU efficiently. A4x20 FLX is a 5.5 CFM fan, but since the surface area is larger, the airflow output is lower as a result. In this setup, an intake case fan is required to compensate the airflow.

It’s much easier to find a silent 120mm chassis fan, so in the end it should still result in a much more silent setup.

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