I have a 2009 Dell Inspiron 1545 laptop with a stock T4500 CPU. I'm looking to upgrade it to a newer or faster CPU. I've seen some people replace theirs with a T9600 but never a T9900. So I'm wondering if it will be compatible with the motherboard and would it be worth the extra $30 from a T9600. I've also read that some people managed to put 8 GB of memory into the same motherboard that has a max of 4GB, how did you do it?