All The Mods 9 (ATM9) is a beast of a modpack that’ll push your server hardware to its limits. With over 400 mods including heavy hitters like Create, Applied Energistics 2, and Mekanism, you’re looking at serious resource demands that go way beyond vanilla Minecraft.
Minimum server requirements for ATM9: 8GB RAM, quad-core CPU (3.0GHz+), and 15GB storage space. For smooth gameplay with 4+ players, bump that up to 12-16GB RAM and a high-performance processor.
RAM Requirements: Why ATM9 Needs So Much Memory
ATM9 is memory-hungry, and there’s no way around it. Here’s what you need based on player count:
- 1-2 players: 8GB minimum, 10GB recommended
- 3-5 players: 12GB minimum, 14GB recommended
- 6-10 players: 16GB minimum, 20GB recommended
- 10+ players: 20GB+ (expect heavy world generation)
The reason ATM9 devours RAM comes down to mod complexity. Industrial mods like Mekanism and Thermal Expansion create tons of tile entities that stay loaded in memory. Add in dimension-hopping with The Twilight Forest and The End reborn, and your server’s working overtime to track everything.
Don’t allocate all your system RAM to the server. Leave at least 2-4GB for the operating system, or you’ll get nasty performance hiccups when the OS starts swapping to disk.
CPU Performance: Single-Core Speed Matters Most
Minecraft’s still largely single-threaded, so ATM9 cares more about your CPU’s single-core performance than having 16 cores. Here’s what works:
Minimum specs:
- Quad-core processor at 3.0GHz or higher
- Modern architecture (Intel 8th gen+ or AMD Ryzen 2000+)
- Good single-thread performance (3000+ PassMark score)
Recommended specs:
- 6-8 core processor at 3.5GHz+ base clock
- High boost clocks (4.5GHz+ single core)
- Intel i5-12600K, AMD Ryzen 5 5600X, or better
The extra cores help with background tasks like world saving, chunk loading, and handling multiple players simultaneously. But when it comes to tick processing and mod calculations, that single-core speed is king.
Why Clock Speed Beats Core Count
ATM9’s heavy automation mods create complex processing chains that run sequentially. A Create contraption with 50 mechanical components needs to calculate each piece in order. More cores won’t speed this up – only faster individual cores will.
Storage and Bandwidth Requirements
ATM9 generates chunky world files, especially with all the new biomes and structures. Plan for:
- Base installation: 15GB for server files and mods
- World storage: 5-10GB for a fresh world, 20GB+ for established servers
- Backups: Another 50-100GB if you’re smart about server management
Use SSD storage. Period. The constant chunk loading and saving will make traditional hard drives a major bottleneck. NVMe SSDs are ideal, but even a basic SATA SSD beats spinning rust.
For network requirements, expect 50-100MB of initial download per player, then 1-5MB per hour during normal gameplay. World exploration spikes this significantly.
Java Configuration for ATM9 Servers
Getting your Java settings right makes a huge difference. ATM9 works best with Java 17 or 19, and these JVM arguments will save you headaches:
-Xmx12G -Xms12G -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8m -XX:G1ReservePercent=20
Adjust the -Xmx12G and -Xms12G values to match your allocated RAM. Setting them equal prevents Java from constantly resizing the heap.
Common Java Performance Mistakes
Don’t use these outdated arguments you’ll find in old tutorials:
-XX:+UseConcMarkSweepGC(deprecated)-XX:+CMSIncrementalMode(removed in newer Java)- Anything mentioning PermGen (not relevant for modern Java)
Network and Hosting Considerations
Self-hosting ATM9 requires serious upload bandwidth. Each player needs consistent data flow, and lag spikes kill the experience with complex automation setups.
Upload speed requirements:
- 2-3 players: 10Mbps minimum upload
- 4-6 players: 25Mbps recommended
- 8+ players: 50Mbps+ (consider dedicated hosting)
Home internet upload speeds often can’t handle larger groups. That’s where professional game server hosting shines – you get enterprise-grade connections and hardware optimized for modded Minecraft.
GameTeam.io offers high-performance ATM9 servers starting at $1/GB, with automatic mod installation and 20% off for new customers. No wrestling with Java arguments or bandwidth limits.
Real-World Performance Testing
I’ve tested ATM9 on various hardware configurations, and here’s what actually happens:
8GB RAM server: Works for 1-2 players doing basic progression. Starts struggling when anyone builds serious automation or explores aggressively. Expect 15-20 TPS under load.
12GB RAM server: Sweet spot for small groups (3-4 players). Handles most automation without issues. Occasional hiccups during heavy world generation.
16GB+ RAM server: Smooth experience for larger groups. Can handle multiple players running quarries, complex Create builds, and dimension hopping simultaneously.
Performance Monitoring
Keep an eye on these metrics:
- TPS (Ticks Per Second): Should stay at 20. Below 15 is noticeable lag.
- RAM usage: If you’re using 90%+ consistently, upgrade.
- GC pause times: Over 500ms causes noticeable stuttering.
Use tools like Spark profiler or built-in server monitoring to identify performance bottlenecks before they become major problems.
Frequently Asked Questions
Can I run ATM9 server on 6GB RAM?
Technically yes, but you’ll hit constant memory pressure with just one or two players. It’s not worth the frustration – invest in proper RAM allocation.
Does ATM9 work better on Linux or Windows servers?
Linux typically offers 10-15% better performance due to lower OS overhead. Ubuntu Server or CentOS are solid choices if you’re comfortable with command-line management.
How often should I restart an ATM9 server?
Daily restarts help clear memory leaks from mods. Set up automatic restarts during low-traffic hours to maintain optimal performance.
Can I upgrade server specs while keeping my world?
Absolutely. Just backup your world folder before migrating. RAM and CPU upgrades are seamless – your players won’t lose any progress.
Making the Right Choice for Your Group
ATM9 server requirements aren’t negotiable – this modpack demands serious hardware. Skimp on specs and you’ll spend more time troubleshooting than actually playing.
For small friend groups, a well-configured 12GB server handles most scenarios. Larger communities need 16GB+ and should seriously consider professional hosting to avoid the headaches of home server management.
The investment in proper hardware pays off in smooth gameplay, reliable uptime, and the ability to fully experience everything ATM9 offers. Check out our guide on setting up modded servers for more technical details on getting started.
