I have been told, but don't know myself, that some newer GPS receivers will give a fix using only ephemeris data if the almanac is stale. That will seem like a warm start.

The problem is that once a current almanac is available the fix may mysteriously shift once current drift and error are available a few minutes later, and the fix may shift a lot if it turns out that satellite was in testing or broken and not really part of the constellation at all.

What make & model GPS are you discussing? The manual may be online and indicate how it handles cold starts. Remember that it needs to be left off for *months* to force a cold start.