I compared the performance of both overclocked drives (a 48126S and a 40125W) and no surprise, the cdr writing performance is very similar. On testing 10 blank media only the TDK Blue made by Ritek benefitted from the latest drive by showing a slight increase in maximum writing from 46x to 48x.
Unfortunately I did not have access to 24x cdrws and was unable to check the actual maximum rewrite speed.
It is worth remembering that using 650Mb CDR blanks with the new CAV drives will never give you as fast a burn time as using a 700Mb blank eg at 48x speed a 650Mb file will take about the same time to burn as a 700Mb file. If you do not use the entire capacity of any blank cd, you will never achieve the maximum speed it is capable of.