Making Your Odroid-XU4 a Silent Beast with the Zalman ZM-NB47J

As some of you may know the current top-of-the-line Odroid-XU4 is probably the most powerful SBC on the market. With its 2.0GHz Exynos Octacore CPU, 2GB LPDDR3 and USB3.0 support, it’s hard not to resist its potent charms. But with great power comes, errr, great noise. These things will keep you up at night.

The biggest issue facing the XU4 is heat – this thing gets seriously warm. The default SKU, along with the starter pack, ship with a whiny, annoying, and downright offensive fan. This thing could torture even the most taciturn of folk.

The makers behind the line, HardKernel, do offer a passive cooling solution. It uses a larger, fanless heatsink at 40 x 40 x (H)25mm. While this seems an obvious solution, it does comes with a few caveats. For one the heatsink is only capable of cooling the CPU up to levels around the 1.2GHz mark. Once the system is at full load, thermal throttling will occur. A lesser issue, but still a minor inconvenience, is the fact it no longer fits in the official case.

When I first bought the XU4 I had no idea the fan would be that bad. According to the official site ‘it barely kicks in’. Well I can tell you that is false. The eMMC in my starter pack came preloaded with UbuntuMATE, which is a fairly lightweight OS. Even general navigation would cause the fan to flare up and wind down every 30 seconds or so.

My eventual aim for the device was to configure it as a NAS, and maybe even get a Plex server up and running. I thought being mostly in an idle state would mean things shouldn’t be too bad. I was wrong. This thing was setup in the corner of my bedroom and would regularly wind up at 4am like a jet fighter. That fan had to go.

I looked around online for solutions, and thought maybe the official passive heatsink might be the best option. After all, it had the mounting holes, and was obviously made to fit the device. I wanted more, though. More cooling, less throttling. I started researching based on the 40 x 40mm footprint. There were quite a few options, mainly northbridge heatsinks, but most relied on thermal putty for application.

I finally stumbled upon the Zalman ZM-NB47J, a northbridge heatsink measuring in at 37 x 37 x (H)47mm. It offered a similar footprint to the HardKernel solution, but at nearly twice the height, would offer far better thermal dynamics. The dealbreaker was the fact it had adjustable mounts, meaning it just about fits the XU4. A bit of Arctic Silver 5 later and it was done.

Odroid-XU4 with Zalman NB47J Heatsink

So how does it perform? Well, the fact it doesn’t make a noise means infinitely better in my eyes. Granted the system will still throttle under full load, such as transcoding a 1080p video file. But after a few benchmarks I measured the CPU would run as high as 1.6GHz under load before throttling kicked in. A full 33% increase in performance over the Hardkernel passive heatsink. Not too shabby.

The main problem is finding one of these things. Zalman don’t make them anymore, so your best bet is eBay. Mine cost me about £5 including postage. A small price to pay for a peaceful night’s sleep, I’m sure you’d agree.

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