Why does my game run out of memory when there's free memory available?

That's a classic symptom of memory fragmentation: the free memory is broken into scattered gaps too small to satisfy a large allocation, so an out-of-memory failure occurs even though the total free space would be enough. The allocation can't find a single contiguous block of the needed size among the fragments. This is especially impactful on memory-constrained devices and over long sessions where fragmentation accumulates. Recognizing OOM failures despite apparently-available memory points at fragmentation as the cause.

How do I reduce memory fragmentation?

Control your allocation patterns: use memory pooling and reuse (allocate memory once and reuse it instead of constantly allocating and freeing), reduce the variety of allocation sizes so freed space can be reused, separate short-lived from long-lived allocations to avoid leaving gaps, and minimize allocation churn. These keep memory from fragmenting into scattered gaps over time, so it stays usable for large allocations. Pooling is especially effective because it reuses fixed-size blocks rather than creating new fragmentation with each allocate-and-free cycle.

What Causes Memory Fragmentation in Games?

Quick answer: Memory fragmentation happens when repeated allocation and deallocation of different sizes leaves memory in scattered free gaps, so no contiguous block is large enough despite enough total free memory. From allocation patterns over time.

Memory fragmentation is a subtle problem where your game can fail to allocate memory even though there seems to be enough free. It comes from how memory is allocated and freed over time. Here's what causes memory fragmentation in games.

How Fragmentation Happens

Memory fragmentation occurs when the free memory becomes broken into many small, scattered gaps rather than contiguous blocks, so a large allocation fails even though the total free memory would be enough.

Repeated allocation and deallocation of different sizes, freeing blocks leaves gaps that don't match future allocation sizes
Long-running sessions, fragmentation accumulating over time as the allocation pattern continues
Mixing short and long-lived allocations, transient allocations interspersed with persistent ones, leaving gaps when the transient ones free
Many different-sized allocations, varied sizes making it hard to reuse freed space efficiently
No pooling or reuse, allocating and freeing constantly instead of reusing memory

The result is scattered free memory: even with enough total free space, no single contiguous block is large enough for an allocation, causing a failure.

Why It Causes Out-of-Memory Despite Free Memory

Fragmentation's defining symptom is an out-of-memory failure while there's seemingly enough free memory, because the free memory is fragmented into gaps too small to satisfy the allocation. This is especially impactful on memory-constrained devices and over long sessions.

Bugnet captures memory-related crashes over real sessions, so out-of-memory crashes that may involve fragmentation surface, especially the long-session ones. Recognizing OOM crashes that occur despite apparently-available memory can point at fragmentation.

Reducing Memory Fragmentation

Reducing fragmentation means controlling allocation patterns: use memory pooling and reuse (allocate once, reuse instead of constantly allocating and freeing), reduce the variety of allocation sizes, separate short and long-lived allocations, and minimize churn. These keep memory from fragmenting over time.

Bugnet captures the memory crashes that fragmentation contributes to, helping you see the problem. So memory fragmentation comes from allocation and deallocation patterns over time leaving scattered gaps, and reducing it means pooling, reuse, and controlling allocation patterns so memory stays usable.

Memory fragmentation comes from repeated allocation/deallocation of varied sizes over time, leaving scattered free gaps. It causes out-of-memory failures despite free memory. Reduce it with pooling, reuse, and controlled allocation patterns.