Best answer: Synology DS420+ can technically stream 4K media to compatible devices; just don’t go and try to do some serious transcoding to multiple devices.

Decoding vs. transcoding 4K media with Plex on the DS420+

There’s a substantial difference between the decoding and transcoding of media, especially 4K. The former requires the simple processes of the NAS streaming the said file to a compatible device like a PC. The receiving device simply needs to support the format the file is stored as. The Intel Celeron J4025 CPU inside the DS420+ barely has to do much work to achieve this. 4K is bliss when everything supports the same file.

The issue becomes apparent when you try and transcode 4K media. When your TV or receiving device doesn’t support the filetype, the DS420+ would need to transcode the file into one it does for streaming. This is when the CPU needs to really do some work. This NAS and the processor can technically transcode 4K content, but it’s not perfect, and you will encounter stuttering if other tasks are running on the NAS.

4K transcoding is a mixed bag on the DS420+

The Synology DS420+ comes with the Intel Celeron J4025 CPU, a dual-core processor without Hyperthreading. It’s clocked at 2.0GHz with a boost speed of 2.9GHz. To break through this jargon, it’s a reasonably powerful CPU for a NAS. The issue comes with transcoding 4K content, which is incredibly CPU intensive.

The DS420+ isn’t a budget-friendly NAS, but if you want to do some intensive tasks like 4K transcoding, you’ll, unfortunately, need to spend more. QNAP has a good selection of NAS models with Intel Core i3 and i5 processors. These CPUs are vastly more powerful than Celeron processors, making 4K transcoding a far easier goal to achieve.

4K transcoding on the DS420+requires Plex Pass

One factor to keep in mind when it comes to hardware transcoding is you need Plex Pass to do it with the Plex Media Server. If you only have a free account, you’ll need to rely on software transcoding. You may encounter some buffering or other related issues if relying on this method.

Paying out for Plex Pass will ensure you’re taking advantage of the hardware you have available. You have the choice of three plans: $5 per month, $40 annually, or $150 for lifetime access. The one-off payment of $150 would save you a lot of money in the long run, especially if you have everything set up for years of use.

Solid NAS

Synology DS420+

$500 at Amazon

Four-bay NAS

Synology gave the DS418 a refresh for 2020, throwing in a new faster Intel Celeron J4025 processor and DDR4 RAM. It’s a great little server that can even run Plex.

High-end NAS


$1,952 at Amazon

You can do everything and so much more

If you have a budget that could cover the expense of the QNAP TVS-882 and need a server that can handle larger 4K movies, look no further than this NAS. It has an Intel Core i3-6100 processor, but QNAP does have models available with i5 and i7 CPUs if you need even more performance.

Better streaming

Plex Pass

From $5/mo. at Plex

Stream everything

Plex is an excellent platform for managing, storing, and streaming all your multimedia, including 4K movies. The Plex Pass adds a whole number of benefits that are handy for a NAS owner.