Lag often comes from a setting, the world, or a player’s connection, and more RAM fixes none of those. Before you upgrade, check which kind of lag you have: the server, a player’s connection, or a player’s own computer.
Server crashed or stopped instead of slowing down? See Server Won’t Start or Keeps Crashing?
Step 1: Which kind of lag is it?
| What players see | What it is | Next |
|---|---|---|
| Everyone lags at the same moment: mobs stutter, blocks and items are slow to respond, everyone rubber-bands | Server lag. The server is falling behind its tick rate. A Minecraft server runs 20 ticks per second (TPS), and the console may show Can't keep up! Is the server overloaded? | Step 2 |
| One or a few players lag or have high ping, while others are fine | Connection lag between those players and the server | Connection lag |
| One player’s game stutters or has a low frame rate (FPS) | Client lag. Frames are drawn by the player’s own computer, so a server upgrade won’t raise FPS. | Lower their video settings, or remove shaders and heavy client-side mods. |
On Minecraft, Spark shows your TPS and what is using each tick. Can't keep up! tells you the server is behind, not why. If TPS holds at 20 while everyone lags, the server is keeping up: check Connection lag.
Step 2: Check whether memory is the limit
Open the CPU Usage and Memory Usage graphs below the console (see Usage Graphs) while the lag is happening, not afterwards.
- Memory well below your plan’s limit: RAM isn’t the cause, and more of it won’t help. Go to Step 3.
- Memory pinned at the limit, with lag spikes and then a crash: the server is running out of memory. See Out of Memory (OOM) Crashes.
- Memory near the limit with nobody online, or climbing over hours until a restart: see Reading the Memory Graph before you upgrade.
- Memory near the limit while players lag, but no crash: normal for Minecraft. Java keeps the memory it’s given, so a full graph doesn’t mean RAM is short. Check CPU below, then go to Step 3.
- CPU high while it lags: the game is busy generating terrain, ticking entities, or running a heavy mod. Go to Step 3. For how CPU is shared, see How CPU Fair Usage Works.
- CPU and Memory both low while everyone lags: the server isn’t straining. Go to Connection lag.
Step 3: Match it to the fix
Before you change settings or remove mods, take a manual backup so you can undo it.
| What you see | What to do | Will more RAM help? |
|---|---|---|
| Lag when players explore new areas | Pre-generate the world. Minecraft: Chunky. | No |
| Lag grows with player count, farms, or mobs, and CPU is high | Tune the game. Minecraft: Server Optimization. Terraria: Fixing Lag. 7 Days to Die: Blood Moon Performance. Hytale: Server Performance. | Rarely |
| Lag started after you added a mod or plugin | Remove the newest addition and test again. See Find Which Mod or Plugin Is Causing Problems. | No |
| A short hitch on a regular timer | Usually the world saving. Valheim: see Backup Interval. | No |
| Lag builds over hours and a restart clears it | Schedule a daily restart. | Try the restart first |
| Memory pinned at the limit, lag spikes, then crashes | Follow Out of Memory (OOM) Crashes. | Maybe, after tuning |
The server stops with Not enough disk space | Disk is storage, not RAM. Ask us for more space. See Unmetered Storage. | No |
| Valheim, everyone plays on Steam, and players see desync | Turn off crossplay. See Enable Crossplay. For other Valheim causes, see Lag and Desync on Valheim Servers. | No |
Connection lag
- Have the lagging player use a wired connection instead of Wi-Fi, then run an MTR to your server.
- Everyone has high ping while CPU and Memory are low? Your players may be far from the server. You can change your server’s location.
- Why ping changes: see Understanding Latency.
When more RAM is the answer
Upgrade when out-of-memory crashes continue after the steps in When to Upgrade RAM, or when your game or modpack needs more as a baseline. For Minecraft sizing, see How Much RAM Do I Need for a Minecraft Server? To change your plan, see Upgrade or Downgrade Your Service.
Still Not Working?
Capture this while the lag is happening, then send it on Discord or in a support ticket:
- Your Server UUID
- The time it happened, with your time zone
- How many players were online, and what they were doing
- A screenshot of the CPU Usage and Memory Usage graphs
- A log link from Upload logs beside the console
- On Minecraft, a Spark profile taken during the lag
- If only some players lag, an MTR from one of their computers
Frequently Asked Questions
Only when the server is running out of memory: the Memory Usage graph is pinned at your plan's limit, with lag spikes and then out-of-memory crashes. On Minecraft, memory near the limit with no crashes is normal. If memory is well below the limit while players lag, look at your settings, your world, or the connection instead.
No. Frames are drawn by each player's own computer, so a server upgrade won't raise FPS. Lower the player's video settings, or remove shaders and heavy client-side mods.