SSD NAS for Roon/Plex/maybe some container stuff

[Enquiries]

Hoping you can help with best NAS to get:
• NAS will be in a quiet living room, so drive/fan noise is a big issue.
Currently I have an iMac connected to a number of hard drives, which I've slowly over the years been swapping from HDDs to SSDs, which has definitely made things much better. A faint fan hum is not the end of the world, but definitely hearing disk drives clicking and whirrling is a big problem. Does Qnap tbs-h574tx make too much noise even with heat sink attachments??
• I require a pretty large amount of storage. I'd ideally like something like an Asus Flashstor 12 Pro because at absolute bare minimum I'd want 24TB (formatted) of space and ideally a bunch more than that for expansion as in the ideal world I'd like this to be partly for media center and partly for work files (video editing and animation sequences).
• Of critical importance is for this NAS to be a top notch ROON server. I'll also use Plex as well.
• want 10gbps ethnt & good USB or Tbolt connect.

[ed]

If you need a quiet SSD-based NAS for Roon, Plex, and high-speed storage, you have a few good options, but each comes with trade-offs.

1. ASUS Flashstor 12 Pro (FSR-12 Pro) – Best for All-SSD Storage & Low Noise
12x M.2 NVMe slots (Silent operation, no HDD noise)
2x 10GbE + 2.5GbE ports for fast network access
USB 3.2 Gen 2 (but no Thunderbolt)
Low power draw and compact design
Runs Plex & Roon well, but CPU (N6005) limits hardware transcoding
? Best If: You want a completely silent all-SSD NAS and can deal with the CPU limits on heavy Plex transcoding.

2. QNAP TBS-h574TX – Best for High-Speed Storage & Direct Connections
5x M.2 NVMe slots + Thunderbolt 4 + 10GbE
PCIe 4.0 slots (future expansion for GPU/NIC)
ZFS support (QuTS Hero) for better redundancy
More powerful CPU (i3-1315U) than Flashstor, better for Plex
Uses fan cooling, so may not be 100% silent
? Best If: You need Thunderbolt + 10GbE and more CPU power for Roon & Plex, but fans may still be audible (quieter than HDDs, but not fully silent).

3. QNAP TVS-h874 (i5/i7 Model) – Best Performance, But Not SSD-Only
Supports NVMe SSDs + HDDs (for massive expansion)
10GbE & PCIe slots for future upgrades
Much stronger CPU for Plex transcoding
Not silent, but fan noise can be controlled
? Best If: You want performance over silence and don’t mind HDDs or a larger NAS.

Final Recommendation
If silence is the priority, Asus Flashstor 12 Pro is your best bet—it’s fanless with no HDD noise and great for Roon. However, if you need Thunderbolt and better CPU power for Plex, the QNAP TBS-h574TX is the better choice but will have some fan noise.