I didnt know where else I could ask this question

I had Imation discs that I ran out of that could burn at multiple speeds (the maximum escapes me right now) So I went out and bought some Sony cd-rs that are 700mb and pressumably 48x max speed. I really dont know since I threw away the wrapper and I went to BestBuy today and looked at the same looking cds that said 48x on them.

Anyways, when I open Nero 6 up and go to the burn tab, it only says I can burn at 8x maximum with the Sony discs. But when I put in a Memorex CD-R that lists it as 16x multi speed on its wrapper, it can burn at 16x in Nero.

In further playing around with Nero, I do a 'Speed Test' and the disc comes back saying it can burn at 66.2x (9,940 Kb/s) where as Im stuck with the option of only burning at 8x (1,200Kb/s)

-Is it that my Sony discs are messed up or is it Nero not recognizing it properly?
-Is there anything I can do to (re)callobrate the discs so Nero can burn the Sony discs at 16x and up?

Thanks