How Do the > and >= Operators Work With Timestamps?

The > and >= comparison operators, when used with timestamp, return the same values. For example, this SQL statement...

SELECT * FROM ihRawData WHERE tagname=simulation00001 AND
timestamp>='4/1/2001 01:50:00' AND
timestamp<='4/1/2001 04:00:00' AND
samplingmode=lab

...returns exactly the same first result as this statement:

SELECT * FROM ihRawData WHERE tagname=simulation00001 AND
timestamp > '4/1/2001 01:50:00' AND
timestamp <= '4/1/2001 04:00:00' AND samplingmode=lab

The first result is timestamped at 1:51:00.