How to Enable Genlock

Last updated 2 August 2026

How to Enable Genlock

Genlock locks the sync group's timing to a common reference so every output on the server refreshes on the same frame boundary. Enable it when an edge-blended projection or a multi-display video wall shows visible tearing at the seams between outputs.

Requires the Administrator role and an NVIDIA Quadro Sync board (or equivalent GSync-capable hardware) installed in the server. The Genlock tab only appears when the driver detects compatible synchronization hardware. If the tab shows "No Quadro Sync / GSync hardware detected on this server", the hardware is missing or the driver does not recognise it.

[USER-ACTION-REQUIRED: Attach a screenshot of the Genlock tab showing the Sync source dropdown, the per-output checkboxes with their states, and the Apply genlock button]

Before you start

  • You are signed in to System Management as an Administrator
  • An NVIDIA Quadro Sync board (or compatible GSync hardware) is installed and detected by the driver
  • The outputs you want to synchronize are connected and active
  • If using an external house sync signal, the BNC cable is connected to the sync board's input
  • Any Mosaic grids are already built

Steps

1. Open the Genlock tab

In the System Management sidebar, under Configure > GPU, select Genlock.

2. Choose the sync source

Set Sync source to one of three options:

  • Auto (external reference if a signal is present) — uses the BNC house sync signal when one is detected, otherwise falls back to the timing server's own clock. This is the default and the safest choice for unattended operation, because each reboot re-evaluates whether a signal is present.

  • Internal (timing server's own clock) — the GPU's own vertical sync drives the timing. Use this when all outputs are on a single server with no external reference.

  • External house sync (BNC input) — an external reference signal on the sync board's BNC input drives the timing. Use this when the server must lock to a facility master clock, a broadcast genlock generator, or another server's sync output.

Next to the dropdown, a status line shows what the card currently reports: the active source and whether a house sync signal is present (including its frequency in Hz when detected).

3. Tick the outputs to synchronize

Each connected output appears as a checkbox, listed by connector, port, and monitor name. Tick every output that should be part of the sync group. To include all connected outputs at once, use the Select all checkbox above the list.

Each output shows its current state in parentheses:

  • timing server — this output provides the timing reference for the sync group.

  • client — this output locks its timing to the timing server.

  • unsynced — genlock is not active on this output.

When no outputs are currently synced, the page pre-selects every output — since genlock is typically applied to the whole wall.

Above the output list, a per-GPU status line reports whether the card's timing is in sync or not in sync, and whether a sync signal is available. This is the authoritative lock indicator — individual output states may be absent in some configurations (such as outputs inside a Mosaic grid that are off the desktop).

4. Apply genlock

Select Apply genlock. The ticked outputs are submitted as one set. The first output that can act as timing server becomes the timing server; the rest become its clients. Unticked outputs are removed from the group.

Syncing can take a noticeable amount of time — the page shows elapsed time while the card re-syncs. When it finishes, the page reloads and shows the new state. Confirm that the per-GPU line reads timing in sync.

5. Make it persistent

Genlock state is replayed on startup and after display-layout changes when those toggles are enabled on the Options tab. Enable Restore Settings on Startup and Restore Settings on Display Change once genlock is verified.

Options explained

Setting

Description

Values / Range

Sync source

The timing reference the sync group locks to. Controls whether the GPU uses an external BNC signal, its own clock, or auto-selects based on BNC signal presence.

Auto · Internal (timing server's own clock) · External house sync (BNC input)

Select all

Tick or untick every connected output at once.

Checkbox

Per-output checkbox

Include this output in the synchronized group. The driver assigns one as timing server and the rest as clients.

Checkbox per output

Per-output state (read-only)

The current synchronization role of this output.

timing server · client · unsynced · unsynced, client only · no sync state reported

Per-GPU status (read-only)

Whether the sync card's timing is locked.

timing in sync · not in sync · (no sync signal)

Card reports (read-only)

The sync source the card is currently using and whether a house sync signal is present on the BNC input, including its frequency.

e.g. "VSync · house sync signal present (60 Hz)"

Common Mistakes

  • Genlock tab shows "No Quadro Sync / GSync hardware detected". The server has no sync board or the driver does not detect it. Verify the hardware is installed and the driver is current.

  • Per-GPU status stays "not in sync" after Apply. The card may need a moment to lock, or the sync signal is missing. Check the card-reports line for "no sync signal" and verify the BNC cable if using external sync.

  • Outputs show "no sync state reported". The sync card's topology does not list those outputs — this can happen when outputs are in a Mosaic grid or off the desktop. The per-GPU status is still authoritative for whether the card is locked. Ticking the outputs and applying still works.

  • Selecting External house sync with no BNC signal. The card-reports line shows "no house sync signal" and the card may fail to lock. Verify the reference generator is running and the BNC cable is connected.

  • Forgetting to enable Restore Settings on Startup. Without it, genlock state reverts to the driver default after a reboot. Enable the toggle on the Options tab once genlock is verified.

Tips

  • In a multi-projector edge-blended setup, tick every output. A single unsynchronized projector causes a visible tear line at the blend seam.

  • Auto is the safest default for unattended servers. It re-evaluates on every boot and display-layout change, so it tracks a reference signal that may not always be present (e.g. during maintenance).

  • External house sync is the right choice when several servers must lock to the same reference — for example, in a cluster where each server drives part of a continuous projection.

  • After enabling genlock, open Maintain > GPU Status to confirm each output still shows OK link bandwidth. Genlock does not change bandwidth, but it is a good checkpoint before the show.

How to Set Output Color Format, Bit Depth and Range — set output color format, bit depth and range on the same outputs.

Display Startup Options and Resetting the Display Configuration — enable Restore Settings on Startup so genlock state survives a reboot.

How to Check GPU Output Signal Status — check GPU output signal health after changing the sync configuration.

Display and GPU Configuration — the other GPU tabs and the order to work through them.

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