The Compare
method compares strings in a local-aware fashion, so it has to convert
the Unicode code of each character into a numeric value that reflects
its position in the current culture's alphabet. For example, the
Compare method considers the "b" lowercase character to come
immediately after the "A" uppercase char and before the "B" uppercase
char, even though the "A" and "B" characters are contiguous in the
Unicode character set. This conversion activity takes time and consume
CPU cycles, so you'll find that VB.NET is less efficient than VB6 at
comparing strings. Using the = operator and other comparison operators
doesn't help at all, because they map to the Compare method behind the
scenes, so these operators suffer from the same performance loss.
If you are only interested in checking whether two strings contain the same characters (in a case-sensitive comparison), you can speed up your code by using the CompareOrdinal shared method. This method is 3-4 times faster than the Compare method (or the = operator) because it just scans the two strings and compare the Unicode numeric code of each character.
