What a Memory Leak Actually Is
A memory leak occurs when a program allocates heap memory but never releases it back to the operating system. Over hours or days, the program's memory footprint grows continuously — 200 MB becomes 800 MB becomes 2 GB — consuming RAM that other programs need. Unlike legitimate high memory use (a video editor holding large files in memory, which releases on close), a leaking program's memory grows monotonically and does not decrease even when idle. The signature is the 'sawtooth' or steady climb pattern visible in memory monitoring tools.
Memory Leak vs. Legitimate High Usage
Not every program using 2 GB of RAM has a leak. Chrome legitimately consumes large amounts because each tab runs in a separate process with its own memory space. The diagnostic distinction: legitimate high usage is proportional to workload (more tabs = more RAM, fewer tabs = less RAM) and stable when workload is constant. A leak grows over time with constant workload. If a program uses 500 MB after 1 hour and 1.5 GB after 8 hours with no change in what you're doing, that's a leak. If it uses 1.5 GB because you have 40 browser tabs open, that's expected.
Diagnostic Methodology
Step 1: Open Task Manager, add 'Private Working Set' and 'Handles' columns. Sort by Private Working Set. Note the top 5 processes and their current values. Step 2: Wait 2-4 hours without changing workload. Re-sort — if a process has grown significantly (30%+ increase) while idle or under constant workload, it is the prime suspect. Step 3: Check handle count — handle leaks (file handles, registry keys, GDI objects not released) often accompany memory leaks. A handle count growing by hundreds per hour is diagnostic. Step 4: Verify with Resource Monitor's memory tab for commit charge details.
Common Culprits and Fixes
Browsers: JavaScript memory leaks in single-page web apps. Fix: close and reopen the tab, or restart the browser. GPU Drivers: NVIDIA and AMD drivers occasionally leak VRAM tracking structures. Fix: update to latest driver version; DDU (Display Driver Uninstaller) for clean reinstall if persistent. Windows SysMain/Superfetch: pre-loads frequently used applications but can overcache. Fix: if RAM is consistently above 90% with SysMain consuming significant resources, disable via services.msc. Background sync services (OneDrive, Dropbox, Google Drive): file change monitoring can leak handles on large directory trees. Fix: update the sync client or exclude large directories from sync.
