Does Windows flush drive caches on standby?

Solution 1:

The answer is yes according to this MS Support article + some "Sherlock Holmes deductions":

The FLUSH CACHE command is not issued and the hard disk may become corrupted when you enter standby or hibernate

MSKB 331060

This article apply to Microsoft Windows XP Service Pack 2 and MS issued an HotFix to correct the problem therefore we can assume (!? ;) ) that a Flush Cache Command is issued each time Windows XP (an later?) enter in standby mode. I found no other article issued by MS to clarify this point but this is the well known obscure MS communication style...

Solution 2:

It depends on the hardware settings for the drive.

A drive that Windows recognizes as a removable drive by default has the write cache turned off, which generally makes it safe to remove without "ejecting" the drive.

http://lifehacker.com/5863810/do-i-really-need-to-eject-usb-drives-before-removing-them

Hope that helps.