I reinstalled Diskeeper 12 Professional and undid the changes made by msconfig. the post you made saying possible involvement of the O2 driver (o2sdgx64.sys) seems to have been the missing key I was looking for. I will put some stress on my system later today or tomorrow. Readyboost is also no longer being turned off at random on the drive letter I have assigned to the SD card. it even looks like even the ReadyBoost Driver log has stopped logging eventid 27;
"
A ReadyBoost cache was deleted due to repeated I/O failures on the associated device. This typically happens when the device (e.g. an SD card) is removed, but it may also indicate faulty hardware.
Device name:
Cache path: \Device\Unknown
and
A ReadyBoost cache was deleted due to repeated data corruption instances on the associated device that have been detected and handled. While ReadyBoost will always detect and handle these errors, repeated corruption instances may mean that the ReadyBoost device has worn out which reduces its performance. You should consider replacing the ReadyBoost device.
Device name: O2Micro SD
Cache path: \Device\HarddiskVolume6\ReadyBoost.sfcache "