SyncFolder — Desktop User Guide
Performance Settings
The Performance Settings section controls how much of the available system resources SyncFolder uses during a task run, and whether write operations to the destination are rate-limited. Tuning these settings can help balance synchronisation speed against the impact on other running processes, network infrastructure, or storage devices.
Settings Overview
| Setting | Type | Default |
|---|---|---|
| Synchronization speed | Select | Standard |
| Bandwidth limit | Numeric input (kB/s) | 0 (no limit) |
Synchronization Speed
Controls the degree of parallelism SyncFolder uses during two phases of a task run: file change detection (when content comparison via checksum is enabled) and file copy operations. Three options are available: Low, Standard, and High.
Higher parallelism generally means faster throughput, but the actual benefit depends on the type of storage device involved. Devices that handle concurrent operations well — such as local SSDs — benefit more from higher settings than devices with limited concurrency, such as NAS shares or USB sticks.
Thread counts per device type
The number of parallel threads used for each speed setting depends on both the type of storage device and the size of the files being processed. Files larger than 1 MB are treated as large files; all others are treated as small files.
| Device type | File size | Low | Standard | High |
|---|---|---|---|---|
| MSC devices (local drives, SD cards) |
Small (≤ 1 MB) | 2 | 4 | 8 |
| Large (> 1 MB) | 1 | 2 | 4 | |
| NAS, USB sticks, OneDrive | Small (≤ 1 MB) | 1 | 2 | 4 |
| Large (> 1 MB) | 1 | 1 | 2 | |
| MTP, FTP, SFTP and similar protocols | All sizes | 1 | 1 | 1 |
Choosing the right speed
| Option | When to use |
|---|---|
| Low | The task runs in the foreground while the system is actively in use, and you want to minimise the impact on other applications. Also appropriate for fragile or slow storage devices where high concurrency can cause errors. |
| Standard | The default for most situations. Provides a good balance between speed and system impact for the majority of device and file combinations. |
| High | The task runs unattended or during off-hours, and maximum throughput is the priority. Most beneficial for local MSC devices with many small files. Has limited extra benefit for NAS or cloud destinations. |
Bandwidth Limit
Limits the write speed to the destination location. Enter a value in kB/s (kilobytes per second, where 1 kB = 1024 bytes). A value of 0 means no limit is applied and SyncFolder writes as fast as the destination allows.
This limit applies to write operations to the destination only. Read operations from the source — including checksum calculations — are not affected.
When to use a bandwidth limit
A bandwidth limit is useful in shared network environments where SyncFolder running at full speed could affect other users or services on the same connection. Typical scenarios include:
- Syncing to a NAS on a shared office network during business hours
- Uploading to a cloud destination (OneDrive, FTP) over a connection also used for video calls or other latency-sensitive traffic
- Running a backup task on a server where disk write bandwidth is shared with other processes
Reference values
| Value (kB/s) | Approximate equivalent | Typical use case |
|---|---|---|
| 0 | No limit | Default — use when no other traffic is competing for bandwidth |
| 512 | ~4 Mbit/s | Light restriction on a slower network or busy shared connection |
| 1024 | ~8 Mbit/s | Moderate restriction — leaves headroom on a standard 100 Mbit network |
| 5120 | ~40 Mbit/s | Soft cap on a Gigabit network while allowing other traffic to coexist |
| 10240 | ~80 Mbit/s | Near-full use of a 100 Mbit connection |
0 for maximum speed. Reserve bandwidth limiting for tasks that run concurrently with other network activity.
Related topics: Advanced Task Settings Overview · General Settings · Sync Actions
Last updated: 1 May 2026