There is no right answer. Despite what others say, php is perfectly suited for a lot of needs. Runtime may be your issue, but you also have to think of supportability.<p>If your looking to optimize your site, as messenlinx suggested yslow is a good place to start. Next, I would suggest looking at your queries, ie a select statement across a big table vs. a more refined query across a smaller data set will do wonders regardless of the language.<p>If your data is updated infrequently, you can look at caching your queries in the data level. If not, maybe look at memcached?