Slow SMB performance

Hello All

Im running into trouble, when connecting to my NAS through SMB:
Windows 11 to TS-431XU with QTS 5.2.3.3006 Build 20250108
They are connected through 10GbE Links with a Unifi Switch inbetween.
Reads are 500-800MBps, so hardware seems to be fine. 4 HGST HUH721212ALE604 Disks in RAID5 SSD cached.

I had the issue also with downloads. But after deactivating SMB Signing, the download speed increased dramatically, but the upload still faces 14-15MBps.

Any ideas, what could cause this issue?

431XeU does not have dedicated cache slots…so if you use 4 HDDs, how are you using cache?

(with the officialy supported, original QNAP PCIe expansion card)
Any contribution to the topic?

Cool your jets or I cool them for you

Disable cache and test again…(QTS is broken)

This NAS normally does 200-300MB/s with just the HDDs (So do not expect anything close to 10GbE)


Almost same numbers with and without caching in both directions.

try a few settings from a post I had done over on the old forums. it may help.

https://forum.qnap.com/viewtopic.php?t=169262