Understanding VPS RAM: Guaranteed vs. Burstable Memory in 2026
A 4 GB RAM VPS from different providers can perform very differently under load. The difference often comes down to whether the RAM is guaranteed or burstable.
Guaranteed RAM
What it is: Physical RAM allocated exclusively to your VM. Even if you only use 1 GB of your 4 GB allocation, those 4 GB are reserved and unavailable to other VMs on the same host.
Performance: Consistent. Memory access times are predictable.
Typical pricing: Higher cost per GB.
KVM virtualisation with dedicated resources = guaranteed RAM. This is what Space-Node VPS provides.
Burstable RAM (OpenVZ / Container-based)
What it is: RAM that is primarily allocated to you, but excess capacity on the host is shared across multiple VMs. Your 4 GB "guaranteed" might be 1 GB hard-committed, with up to 4 GB available to burst into when other VMs on the host are idle.
Performance: Excellent when the host is quiet. Degraded under host contention — when all VMs need memory simultaneously, yours gets throttled back to committed allocation.
Typical pricing: Lower cost per GB of stated allocation.
How to Identify Your RAM Type
# Check virtualisation type
systemd-detect-virt
# kvm = KVM (usually guaranteed)
# openvz or lxc = container (often burstable)
# On OpenVZ, check committed vs. theoretical RAM:
cat /proc/user_beancounters | grep -E "physpages|oomguarpages"
Implications for Game Servers
Game servers (Minecraft, Rust, FiveM) need RAM to be consistently available. A Minecraft server configured for 4 GB JVM heap will crash if the operating system can't satisfy that allocation during garbage collection cycles.
On burstable RAM:
- The server runs fine during off-peak hours
- Under host contention (hosting hour peaks), random crashes occur
- These crashes appear to be "memory errors" but are actually resource starvation
The diagnosis: If your server crashes at predictable times (weekends, evenings) but runs fine overnight, suspect RAM starvation from burstable allocation.