I use a CAT24C33 (4k) EEPROM attached to my 8051. If I write a value to a location that already contains the same value, will the write actually happen?

The reason I ask is that I occasionally re-write a string of bytes in which only one byte has changed from the previous write. I'd like to preserve the EEPROM without overwriting.

I know I could read the byte prior to writing it and do this myself, but does these parts already do that in it's own logic?

Thanks in advance
Javier