How to Fix Lag
Try these first — they're free and solve the problem for most people.
01 Check ping in the server browser before joining
1. Open Assetto Corsa and go to Online 2. In the server browser, find the Ping column — it shows your latency to each server 3. Sort by ping (click the column header) 4. Prefer servers under 60ms for clean racing 5. If your preferred server shows high ping but others are lower, the issue is routing to that specific host 6. Content Manager's server browser (free download) shows better ping information and more filter options
Immediately identifies which servers have good routing from your location. Joining a low-ping server vs a high-ping server is the single biggest improvement available.
02 Switch to Ethernet and disable WiFi
1. Connect your PC to your router with a Cat5e or Cat6 Ethernet cable 2. Open Windows Settings > Network & Internet > Wi-Fi and toggle it off 3. Restart AC and check the server browser ping values 4. If ping drops and stabilises, WiFi was contributing jitter 5. WiFi interference from nearby networks is a common source of intermittent packet loss in AC
Eliminates wireless jitter and intermittent packet loss. In AC, even small amounts of packet loss cause visible car jumping — Ethernet removes wireless as a variable entirely.
03 Close background applications before racing
1. Pause Windows Update (Settings > Windows Update > Pause) 2. Close torrent clients and Steam downloads in the system tray 3. Close browser tabs with video (YouTube, Twitch) 4. Disable cloud sync (OneDrive, Google Drive, Dropbox) 5. Upload congestion causes your car to jump on other drivers' screens, leading to contact you did not see coming
Reduces upload congestion that causes your car to 'freeze' on other players' screens. Particularly important at race starts with large grids.
04 Verify game files if you see checksum errors or crashes on join
1. In Steam, right-click Assetto Corsa > Properties > Local Files > Verify integrity of game files 2. Wait for verification to complete 3. If Content Manager shows checksum errors, ensure your mod versions match the server's — this is a mod issue, not a network issue 4. Checksum errors appear as network errors but are actually local file mismatches
Distinguishes network issues from mod compatibility issues. Checksum failures look like connection problems but are not fixed by any network change.
General network tips (not Assetto Corsa-specific)
05 Enable router QoS to prioritise AC traffic
1. Access your router admin panel (typically 192.168.1.1 or 192.168.0.1) 2. Find QoS or Traffic Priority settings 3. Prioritise UDP traffic on port 9600, or prioritise by application name (acs.exe) 4. This ensures AC packets are sent and received immediately even when other devices on the network are downloading 5. Most effective in shared households with multiple concurrent users
Prevents household traffic from delaying AC packets. Most impactful in households where other family members stream or download during race sessions.
06 Forward ports if your server doesn't appear or you get frequent disconnects
1. In your router, forward UDP 9600 and TCP 9600 to your PC's local IP 2. Also forward TCP 8081 if you host your own server 3. For client play, port forwarding is not required on most NAT configurations, but strict NAT may cause intermittent disconnects 4. Check your NAT type via a network test if disconnects are frequent and not ping-related
Fixes intermittent disconnections on strict NAT connections. Not needed for the majority of players on moderate NAT.
Still lagging? The problem is likely your ISP's routing to the game servers.
PingAim detects Assetto Corsa automatically
No manual config. PingAim identifies Assetto Corsa by process name and routes it through your fastest connection using a kernel-level WFP driver.