Cause:
The issue is the result of Aggressive Link State Power Management (ALPM) on the PCI-Express bus negotiating a lower power state for the link between the controller and disk when there is no activity. When ALPM works, disk requests are queued, the serial link revived, and the queued requests are sent to the relevant disk; this requires a disk that supports ALPM.

Resolution:
Modify the advanced settings of your active power management scheme in Windows to turn PCI Express Link State Power Management off.

Commentary:
Searching for a solution yielded a number of possibilities.

Setting the value of:

as discussed by Derek Seaman did not resolve my issue.

Renaming:

to

as suggested by Paul's Computer Service was also ineffective. At the time I was running the latest set of drivers for my platform. Caveat emptor: the solution I outlined in this article worked for me.

References:
Intel CS-025783 - Possible issues with Windows Vista* and Intel® RAID
Windows 7 Intel SATA/AHCI Lockups
Intel® Matrix Storage Manager Bug

Cause:
From Acronis:

Because of the latest major changes in Windows Vista and Windows 7 native snapshot driver (VolSnap), there were some modifications introduced in Acronis True Image Home 2010 (starting from Build 6029). The Acronis native snapshot driver (snapman) was moved from UpperFilters to LowerFilters to avoid conflicts with VolSnap (which could have lead to backups failure or data corruption in backups). This change may sometimes manifest itself in a freezing Windows Vista or Windows 7 operating system on machines with rare software and hardware configurations.

Resolution:
Download an updated SnapAPI build from Acronis. Unpack it and install with the Disable Logging option set. See Acronis KB6529 for the appropriate link.

Commentary: My hardware configuration is not esoteric; my software configuration is equally banal: an Intel Core i7 X58 system with 6GB of RAM, RAID1 on an ICH10R, and Windows 7 Ultimate 64-bit.

Reference: http://kb.acronis.com/content/6529