A document that opens promptly in the office but takes much longer through QuickConnect may be travelling over a different connection path. That observation is worth recording before replacing NAS drives or changing storage settings. QuickConnect can use a relay when a direct connection is unavailable, and Synology notes that relayed access may be slower because of latency.

The existence of a QuickConnect address alone does not prove that a particular transfer used the relay. Keep the connection mode marked unconfirmed unless the application or relevant diagnostic information actually identifies it. A slower result can also involve the remote internet connection or the operation being performed.

Compare one operation at a time

Choose a non-sensitive file and one supported access method. Record the application, file size, operation and time. Downloading a file, previewing it in a browser and synchronising a folder are different tests; changing all three between locations makes the result difficult to interpret.

On the office network, repeat the chosen operation through the existing authorised local NAS address. Later compare the corresponding remote operation from the intended location. Keep a note of whether the client used wired networking, Wi-Fi or mobile data and whether other transfers were active. This creates a useful record even when exact network routing is not visible.

Inspect configuration before changing exposure

An authorised administrator can review QuickConnect's advanced settings and allowed services in DSM's External Access settings. Record what is enabled and whether the application being tested is covered. Do not disable a working relay merely to see whether speed changes when it may be the only available connection path.

Give the administrator the local and remote results together. A large difference supports investigating the access route; similar slow results point toward a broader workload or endpoint investigation. Neither comparison alone identifies a failed component.

Opening router ports is a separate network-design decision, not a necessary first diagnostic step. Preserve the existing access arrangement while establishing the cause. The useful outcome here is a repeatable transfer comparison with known conditions, plus a clear statement of which connection details remain unverified.

Sources: Synology documentation 1.