W8 may run well for several days, but occasionally hangs for 30' to minutes. Mouse is usable and some window switching is possible, but during the freeze it's essentially dead. Occurs randomly while in browser, other programs, file manager, etc. Sometimes, but not always, a window reports "not responding." If items are clicked during the unresponsive period, they will all execute when the freeze ends. After normal operation resumes there's no event viewer ERROR, but there is a warning at the time of the incident for storahci system: "Reset to device, \Device\RaidPort0, was issued." There is no RAID array on this box. In device manager no RAID driver is shown anywhere. System runs in AHCI mode and W8 drive is a SATA. Under "IDE ATA/ATAPI controllers" there were two entries for Standard SATA AHCI controller. Both indicated that the drivers were current. I downloaded a Marvel 91xx SATA 6g controller, right-clicked one of the above entries and UPDATED. The Marvel driver appeared under the "storage controllers" category in device manager, and one of the two SATI AHCI controller entries vanished. Clicking to upgrade the other SATA AHCI entry stated that no drivers could be found. W8 continues to hang. Hardware/software is identical to that used by W7 on an alternate SSD drive that never hangs. Before W8 CPV, W7 was running on the same SATA drive without problems. Virtually all freeze remedies seen in forums have been tried. Similar problems are widely reported. Perhaps the next W8 incarnation will incorporate a fix.