ReadyBoostMonitor (RBMon) is a third-party software utility designed to track and display real-time statistics of Microsoft Windows’ native ReadyBoost feature.
While ReadyBoost itself uses the fast random-access speeds of a USB flash drive or SD card to act as a temporary memory cache for older mechanical hard drives (HDDs), Windows does not natively offer an easy-to-read, dedicated visual dashboard to see it working. ReadyBoostMonitor solves this by acting as a lightweight interface that translates Windows internal data into readable metrics. Key Metrics Tracked by ReadyBoostMonitor
The utility sits in your system tray or opens as a small graph window to show you exactly how your USB drive is helping your PC:
Cache Space Usage: Shows how much of your allocated USB storage is holding cached files.
Compression Ratio: Tracks how heavily Windows is compressing data inside the ReadyBoost.sfcache file to maximize space.
Cache Read/Write Hit Rates: Identifies if Windows is successfully pulling data from the fast USB drive rather than stalling on the slow hard drive.
Total Throughput: Displays live read and write speeds dedicated strictly to your background cache. How to Check USB Cache Performance Natively
If you prefer not to use third-party tools like ReadyBoostMonitor, you can monitor your USB cache performance using the built-in Windows Performance Monitor: Press Windows Key + R, type perfmon.exe, and press Enter.
Click Performance Monitor under the Monitoring Tools folder on the left pane.
Click the green “+” (Add) button located on the top toolbar.
Scroll through the available performance categories and select ReadyBoost Cache.
Click Add, then click OK to begin viewing live graphs of your USB cache activity. Is ReadyBoost (and ReadyBoostMonitor) Still Useful?
The short answer is no for most modern PCs, but yes for specific legacy hardware.