How to Fix WiFi and Network Drive Issues on a NAS Device: Slow Transfer Speeds, Dropped Connections, and SMB Fixes

A network-attached storage (NAS) device should feel like a fast local hard drive over your home network. When it instead delivers slow transfer speeds, drops connections mid-copy, or disappears from Windows Explorer entirely, the culprit is almost always one of a handful of well-documented WiFi, SMB protocol, or configuration issues. This guide walks through every fix, from the simplest to the most technical.

Why NAS WiFi Performance Disappoints

WiFi introduces three problems that wired Ethernet does not: variable bandwidth, higher latency, and packet retransmission. A typical WiFi 6 connection that shows 500 Mbps on a speed test may deliver only 50–100 MB/s of actual NAS throughput because SMB — the protocol Windows and macOS use to talk to network drives — is sensitive to latency and retransmissions in ways that a web browser is not. Add interference, power management quirks, and outdated protocol settings and you have a recipe for 5 MB/s where you expected 50.

Fix 1: Switch to Ethernet — Even Just for Big Transfers

No WiFi optimization beats a direct Ethernet cable. A single Gigabit Ethernet connection gives you a stable, full-duplex 125 MB/s ceiling with near-zero latency. If your NAS has a 2.5 GbE port — common on modern Synology, QNAP, and UGREEN units — pairing it with a 2.5 GbE switch delivers up to 312 MB/s, far beyond what any WiFi link sustains under real-world conditions.

If running cable is not feasible, consider a MoCA 2.5 adapter pair to carry Ethernet over existing coax wiring. See our guide on MoCA adapters explained for setup details. As a fallback, placing a strong WiFi 6 or WiFi 6E mesh node near the NAS gives better results than relying on a weak signal from a distant router.

Fix 2: Force SMB3 and Disable SMB1

SMB (Server Message Block) comes in three major versions. SMB1 — dating to the 1990s — is still enabled by default on some NAS devices for compatibility. It is both a security risk and a performance killer, adding negotiation overhead that halves real-world throughput compared to SMB3.

On Synology DSM

1. Open Control Panel → File Services → SMB.
2. Set Minimum SMB protocol to SMB2.
3. Set Maximum SMB protocol to SMB3.
4. Enable Opportunistic Locking and SMB Multichannel if your NAS has multiple NICs or a multi-gig adapter.
5. Click Apply.

On QNAP QTS

Go to Control Panel → Network & File Services → Win/Mac/NFS/WebDAV → Microsoft Networking and set the minimum protocol to SMB2 and maximum to SMB3.

On the Windows Client

Open PowerShell as Administrator and run Set-SmbClientConfiguration -MinimumVersion 2.0.2 to prevent your PC from falling back to SMB1 during negotiation.

Fix 3: Disable SMB Signing on Windows

Windows 11 enables SMB signing by default. On a local home network, signing adds CPU overhead without meaningful protection and can reduce NAS throughput by 20–30% on older hardware. To disable it for local transfers, open PowerShell as Administrator and run:

Set-SmbClientConfiguration -RequireSecuritySignature $false -EnableSecuritySignature $false

Re-enable signing if you ever use the PC on untrusted networks or a corporate domain where it is required by policy.

Fix 4: Disable Adapter Power Management

Windows can cut power to your WiFi adapter during brief idle periods. When a large NAS transfer pauses between files in a batch copy, the adapter can drop into a low-power state and take several seconds to return to full speed — the most common cause of transfers that start fast and then slow to a crawl.

1. Open Device Manager and expand Network Adapters.
2. Right-click your WiFi adapter and choose Properties.
3. On the Power Management tab, uncheck Allow the computer to turn off this device to save power.
4. In the Advanced tab, find Power Saving Mode or Wireless Mode and set it to the highest-performance option.

Fix 5: Connect to the 5 GHz or 6 GHz Band

If you must use WiFi to reach your NAS, make sure the connecting device is on the 5 GHz band — or 6 GHz if you have a WiFi 6E router — not 2.4 GHz. The 2.4 GHz band maxes out around 600 Mbps in ideal conditions and is typically congested with neighboring networks; in practice you may see only 20–40 Mbps of NAS throughput on 2.4 GHz versus 80–120 Mbps on 5 GHz from the same location. See our guide on 2.4 GHz vs 5 GHz vs 6 GHz WiFi for a full breakdown of when each band makes sense.

Fix 6: Pause NAS Background Tasks During Transfers

Synology DSM, QNAP QTS, and other NAS operating systems run background indexing, media transcoding, cloud sync, and antivirus scans that compete with file transfers for both disk I/O and CPU. During a large copy, pause or disable:

• Cloud Sync (Synology) or Cloud Drive Sync (QNAP)
• Media Indexer and Photo Station or Moments indexing tasks
• Antivirus or malware scan schedules
• Download Station active tasks

On Synology DSM, open Resource Monitor from the main menu to see which processes are consuming CPU and disk I/O in real time.

Fix 7: Enable Jumbo Frames Only When Fully Supported

Jumbo Frames increase the Ethernet MTU from the standard 1,500 bytes to 9,000 bytes, reducing CPU overhead on large sequential transfers — exactly the pattern of a NAS file copy. The catch: every device on the path must support Jumbo Frames, including the NAS, your switch, and your PC’s network adapter. If even one device does not support the larger MTU, packets get fragmented and speeds actually drop. Jumbo Frames have no effect over WiFi, so this fix only applies to fully wired connections. For guidance on finding the right MTU for your connection, see our article on fixing WiFi slowdowns caused by wrong MTU size.

Quick Checklist

• Use wired Ethernet — or MoCA — instead of WiFi for both the NAS and your PC
• Set minimum/maximum SMB to SMB2/SMB3 on the NAS control panel
• Disable SMB signing on Windows for home-network-only use
• Uncheck “Allow the computer to turn off this device” for your WiFi adapter in Device Manager
• Connect to 5 GHz or 6 GHz if WiFi is your only option
• Pause cloud sync, media indexing, and antivirus on the NAS during large transfers
• Enable Jumbo Frames only if every wired device on the path supports 9,000-byte MTU

Once transfers are running smoothly, run a speed test to confirm your overall internet connection is healthy. If your ISP link is a bottleneck for cloud backups or remote NAS access, it may be time to look at a faster plan or better hardware — see our picks for the best PoE access points for reliable wired coverage throughout a larger home.