Not necessarily the burning speed ... and most burners are optimised for higher speeds these days anyway, so lowering the speed will actually be worse than burning at the rated speed.
Please provide the MID of your CD's.
Skipping (read errors) on cheap media is a very common problem. The only way to fix it is to use better quality media - Without knowing what media you are experiencing problems with, it's pretty hard to determine what the issue could be
Also, what's your burning drive & firmware?