You still havn't told us what brand you bought😛 Anyways, big name laptops use cartridge based cpus, so i dunno if u can check if its stepping. Even if you could, i doubt there is enough cooling for o/c to be wise. Cheapo generic laptops sometimes use desktop chips though.
As for your poor lcd, thats a bummer. Companies all have an allowable amount of dead pixels.. so unless you are past their limit, you get to live with it. I think sony's limit is up to 9 pixels or something, very disturbing🙁