Systema is a free system tuning suite for Windows 10 and 11, built around two things most optimizers get wrong: it uses documented Windows APIs rather than registry folklore, and every change it makes can be undone.

Before any setting is applied, Systema captures the current state. Turning a feature off restores exactly what was there, and where the original value cannot be read it falls back to the Windows default rather than guessing. Changes that Windows or another application reverses are detected and re-applied.

Background app throttling. Task Sleep is modelled on Apple's App Nap. Applications you are not using have their process priority lowered, their memory and I/O priority reduced, and a hard CPU ceiling applied through Windows Job Objects. Foreground and audio-playing applications are left alone, and anything can be pinned to a never-sleep list.

CPU core parking and power. Core Efficiency drives parking depth, minimum unparked cores, and processor clock floors through powercfg on whichever power plan is active. Settings survive reboots, application restarts, and power plan changes. Hybrid processors with efficiency cores are detected and handled separately from older uniform designs. One toggle returns everything to Windows defaults.

Game Boost. Throttles the Windows Search indexer rather than killing it, holds the machine awake with proper power requests that appear in powercfg /requests, and restores page priority on launching applications. It never modifies the game process itself.

Telemetry removal. No Telemetry Pro disables telemetry services, scheduled tasks, and registry policy across Windows, Microsoft Edge, NVIDIA, and Intel graphics, capturing each one beforehand so it can be restored.

Graphics control. NVIDIA frame rate caps and power management mode through NVAPI, and Intel integrated graphics power policy.

Also included: startup impact analysis, a service manager, bloatware removal, memory cleanup, DNS switching, and restore point management.

Systema is free, carries no advertisements, requires no account, and collects no telemetry of its own. Windows 10 and 11, 64-bit, administrator rights required.