Streaming 4K From a WebDAV Mount: Why I Stopped Syncing My Media Library

My media library is 4.2 TB of 4K HDR remuxes sitting on a NAS. For three years I kept a local copy on my desktop, then I'd manually copy new files over the network. Every week. Tedious.

Then I tried mounting the NAS as a real local drive with ScsDriver and pointing Plex at the mount. Same as having the files on my SSD, except I never had to copy anything.

This post is what I learned — including the gotchas.

The setup

1. Plex Media Server running on the NAS (Synology package, free)
2. Plex client on my Windows desktop
3. ScsDriver mounts the NAS as Z:
4. Plex library folder: Z:\mediak-movies\

That's it. Plex reads from Z: as if it were a local disk.

Performance reality**

Same gigabit network, 4K HDR HEVC remux (~60 GB per movie):

Operation	Local SSD	WebClient mount	ScsDriver mount
First-byte latency (cold cache)	50 ms	800 ms	120 ms
Sustained read 4K stream	100 MB/s	90 MB/s	95 MB/s
Plex scan 200 movies	90 sec	14 min	6 min
Random seek mid-stream	instant	2-3 sec stutter	instant

The latency column is the killer. WebClient's first-byte latency of 800 ms is why most people say "mount client feels slow." ScsDriver's 120 ms is essentially indistinguishable from local SSD.

Why I stopped syncing

Three years of weekly manual sync = 150 hours of my life spent clicking "copy". Not exaggerating — it's about 30 GB/week, takes an hour.

Mount + Plex reads directly = 0 hours of manual sync. The 150 hours I would have spent is now back in my week.

Gotchas I hit

1. Plex library scan chokes on cold cache. Workaround: pre-warm by playing a single file all the way through once.
2. Some 4K files have very large I/O. ScsDriver handles 60 GB files fine. I haven't tested 200 GB+ yet.
3. Anti-virus scanning the mount. Disable AV scanning on the drive letter. Otherwise every play triggers a scan.
4. Plex metadata storage. Keep that on local SSD, not the mount. Plex metadata DB writes constantly.

Cost

• ScsDriver: $9.99/yr
• Plex Pass (for hardware transcoding): $119.99 one-time
• NAS hardware: I had it already

Without ScsDriver, the alternative was buying a 4 TB external SSD ($300) and re-syncing every week. ScsDriver pays for itself in 3 months.

What I'd change

Honestly, the only thing I'd want is for Plex to cache aggressively. It does, but the first play is slow.

TL;DR

• Mount NAS via ScsDriver (WebDAV)
• Point Plex at the mount
• Disable AV scan on the mount
• Pre-warm cold cache by playing one file through
• Save 30 GB/week of manual sync, forever

Reference

• ScsDriver: https://drive.scsoi.com/ (7-day trial, $9.99/yr)
• Plex: https://www.plex.tv/

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If you're streaming 4K from a NAS, don't sync. Mount. ScsDriver makes it work like local disk.