[gentoo-user] Excessive digest failures in portage

[Saphirus Sage]

This has been a consistent problem on one of my computers, to no avail
thusfar, even after changing sync server settings or redigesting
individual failed ebuilds. In running emerge -uavDN world, it will take
at least an hour to generate a list of packages to be merged, but not
before ouputting a TON of failed digests. Example below.

gentoog4 proc # emerge -uavDN world

These are the packages that would be merged, in order:

Calculating dependencies   * Digest verification failed:
 * /usr/portage/dev-libs/libgpg-error/libgpg-error-1.7.ebuild
 * Reason: Filesize does not match recorded size
 * Got: 895
 * Expected: 899
 * Digest verification failed:
 * /usr/portage/app-admin/syslog-ng/syslog-ng-2.1.4.ebuild
 * Reason: Filesize does not match recorded size
 * Got: 2523
 * Expected: 2521
 * Digest verification failed:
 * /usr/portage/dev-libs/libmcrypt/libmcrypt-2.5.8-r1.ebuild
 * Reason: Filesize does not match recorded size
 * Got: 870
 * Expected: 875
 * Digest verification failed:
 * /usr/portage/dev-db/sqlite/sqlite-3.6.14.ebuild
 * Reason: Filesize does not match recorded size
 * Got: 2285
 * Expected: 2286
 * Digest verification failed:
 * /usr/portage/app-admin/eselect/eselect-1.0.12.ebuild
 * Reason: Filesize does not match recorded size
 * Got: 1694
 * Expected: 1700
 * Digest verification failed:
 * /usr/portage/dev-db/sqlite/sqlite-3.6.14.1.ebuild
 * Reason: Filesize does not match recorded size
 * Got: 2262
 * Expected: 2263
 * Digest verification failed:
 * /usr/portage/dev-db/sqlite/sqlite-3.6.13.ebuild
 * Reason: Filesize does not match recorded size
 * Got: 2408
 * Expected: 2404
 * Digest verification failed:
 * /usr/portage/dev-db/sqlite/sqlite-3.6.12.ebuild
 * Reason: Filesize does not match recorded size
 * Got: 2321
 * Expected: 2320

So, is this just the crying screams of a failing drive, or is there some
other problem at hand here?