Can't burn DVD's to full 4.7GB

[sojourn]

Hi, hopefully someone can give me a hand with this problem. I have a LiteOn LDW-451S DVD burner on a computer with a widnows xp os. I usally use the RecordNow DX software that came with burner to do my work. When ever I place a blank single sided DVD in my drive, the program is saying that I only have 4.483GB on the DVD.
At first I thought there was a problem with the software so I went and got Nero Ultra 6, but that too is telling me that my blank dvd's have only 4.483 GB free.
Does anyone know how to fix this or this there something I am doing wrong?

[brad]

A DVD-R says it holds 4.7- but thats in Japaneese (Advertising) killobytes- it actualy holds about 4.35GB and a DVD-9 says it can hold 9.4 but it can actualy only hold 7.25
Exactly: The Computer sees 1GB as 1,073,741,824 bytes.
The disc manufactures see 1GB as 1,000,000,000 bytes.
brad

[hell_sent_me]