Speed

Dear all, I have a piece of code which posts a matrix which can be from 1X1 dimension to...the sky is the limit (can be 500X500). In this piece of code I have 2 while loops, nested, which I cannot get rid of.. I'd like to ask you for any suggestions to optimize the posting of the matrix..I already put in action zend optimizer, ---with mm option... Where/what should I tweak more, in order to make the whole thing faster. I am running the system on Win 2k, therefore I cannot use Zend accelerator. Thanks. Mihai