Flash storage devices must meet minimum performance requirements to support ReadyBoost, including:
2.5 MB/s throughput for random 4-KB reads
1.75 MB/s throughput for random 512-KB writes (on Windows Vista)
1.75 MB/s throughput for random 1-MB writes (on Windows 7)
For a device to be designated as “enhanced for ReadyBoost”, it must meet the following higher performance requirements: 5 MB/s throughput for random 4-KB reads 3 MB/s throughput for random 512-KB writes (on Windows Vista)
3 MB/s throughput for random 1-MB writes (on Windows 7)
SuperFetch Improvements in Windows 7:
In Windows 7, SuperFetch still determines page priorities based on recent usage patterns, but it performs more selective prefetching. Windows 7 SuperFetch maintains only the highest priority pages in the ReadyBoost caches. We tested the improvements and confirmed that Windows 7 SuperFetch is more respectful of user presence, further decreasing prefetching while the user is active. These changes reduced SuperFetch’s memory footprint without affecting responsiveness.
Specific changes in Windows 7 SuperFetch include:
Delay SuperFetch’s initial post-boot memory population by several minutes, contributing to the system’s post-boot quiet state.
Better prioritize the private process pages of foreground applications to reduce hard faults from the pagefile.
Significantly decrease prefetching for certain types of files that are now more efficiently retrieved from disk, such as Large and sequential files
MP3s, pictures, ISOs, and videos
Files that are only opened for write (such as log files)
Track long-term memory pressure.
ReadyBoost supports all storage devices that have a Windows Assessment Tool (WinSAT) score of 6.5 and above. For example, ReadyBoost supports the following devices:
USB 2.0 and above flash drives
Secure Digital cards (SD cards)
To determine the WinSAT score of a device, run the following command from an elevated command prompt:
WinSat disk –read –ran –ransize 4096 –drive E
The above command displays the WinSAT score for drive E