AN EXPERT THAT CAN HELPME PLEASE

I have a sony DRU-800A and the specifications says that i can burn
DVD-R at 1x. I put a dvd media that suport 1x-8x burn speed. im used nero 6 AND dvd decrypter lastest version, but the lower speed that i can burn is 4x. I want burn at 1x. if this dvd burner write DVD-R at 1x as mentioned..how i can force it to burn at 1x with nero or dvd decrypter??. i used firmware KY06. nero showme the option of 1x 2x and 2.4x to burn, but when i insert the media in this case (maxell 1x-8x) or (memorex 1x-4x) nero automatically showme that the lower speed is 4x. why this happends if the media's support 1x??

the problem is the dvd burner?? or is the program that im used???