Me also have Lenovo z460 with intel P6200, 2gb RAM. now I upgrade my Lenovo Z460 and become like this:
Processor : Intel i5 460M, 2.5Ghz with turbo up to 2.8Ghz (Second hand from a broken laptop), my ex processor intel P6200 sold for US $ 20
RAM : 8 GB
SDRAM 16 GB for ReadyBoost
Performance like new Laptop. I also looking for second hand intel i7 840QM processor and 500 GB SSD trying to push my laptop to maximum performance.