GTA 6 Server CPU Bottlenecks

The first thing most GTA server owners blame when their server feels laggy is the CPU. They're often right. But about one in three cases of suspected "CPU bottleneck" turn out to be something completely different. Here's how to figure out which you've got.

The signs of a real CPU bottleneck

• Tick rate falls below your set target (60 Hz on most GTA servers).
• CPU usage of the game server process consistently reaches 85%+ during peak hours.
• Server response time to command input worsens linearly as more players connect.
• This behaviour becomes more severe during peak times and less severe during off-peak times.

Should only one or some of these apply, continue reading before purchasing an upgrade.

Things that look like CPU but are not

• Network latency. Players are lagging (pinging slowly), but the CPU graphs look fine. This is a networking issue. See our latency guide for more information.
• Database contention. Scripts spend too long waiting for database queries to complete. This leads to low CPU utilisation (many processes are idle because they are waiting). You should examine the MariaDB slow query log.
• Noisy neighbour. Other customers on shared hosting eating up your CPU time. You see 100% usage, but your processes only receive 20%. Verify by running the same workload on a dedicated box.
• Storage IO. Scripts that write to disk synchronously. This shows up as CPU wait time. Migrate to NVMe or cut down on write-intensive scripts.

Diagnosing properly

Run these Linux commands, in this order:

1. Use top or htop. Is the FXServer process (or its GTA 6 equivalent) using up all the CPU? If so, continue. If not, look elsewhere.
2. iostat 1 10. Are you nearing 100% disk IO utilisation? If so, your storage is the bottleneck, not your CPU.
3. mpstat -P ALL 1. Are all cores in use? Or is one pinned at 100% while others sit idle? If only one, you have a single-threaded hot path.
4. Run pidstat 1. Determine which process is hogging CPU. If it's not your game server, look into that process.

The single-core hot path problem

Historically, GTA servers have had one hot thread responsible for game logic. At high player counts, that thread saturates one core. You could throw 16 more cores at it and it would not help because the work does not parallelise.

Fixes:

• Offload non-urgent logic to background threads. Most frameworks allow this these days. Our script guide highlights scripts that thread well.
• Profile scripts to detect tight loops. Even with a non-public API like GTA 6's, there will be profiling tools.
• Offload heavy IO to async handlers instead of blocking the main tick.
• Decrease entity counts. Fewer peds, fewer objects, improved tick rate. This is the biggest single lever here.

When to upgrade

Upgrade CPU hardware when:

• You've profiled scripts and know they're sane.
• You already run a top-tier Ryzen or Intel CPU.
• You've consistently saturated one core during peak hours for 2 weeks straight.
• You've already tested on dedicated hardware to eliminate noisy neighbour.

The most common mistake is upgrading CPU when what you really have is a bad script. The new CPU will mask the bad script for a few weeks, then the same problem crops up at the next scale step.

Related reading

If you're interested in more general performance tweaking, consult our performance guide. If you're looking to tweak settings, see best settings for high FPS and low ping. For the hardware your server needs per player count, see our hardware requirements page.