Reading/Writing binary files

[opus]

does anybody know if their is a difference in reading/writing time for binary files if i

1.) use for each Value the exact position in the file
Example

Put DatNr,  1, ChangeTime
Put DatNr, 5, ChangeRandom
Put DatNr, 9, LfzX
Put DatNr, 13, LfzY

or
2.) just read/write each value after the other, without handing over the exact position?
Example

Put DatNr, , ChangeTime
Put DatNr,, ChangeRandom
Put DatNr,, LfzX
Put DatNr,, LfzY

Thanks