Maybe you can clarify what do you mean by "what kind"? :sweat:
533Mhz DDR2 tio si 533Mhz DDR2......there is no other kind of 533Mhz DDR2...Unless you're talking about the brand...for this instance it doesn't matter any brand, as long as it's 533Mhz DDR2 or higher it will work.....alternatively you can open up the ram compartment to see what is the original one :thumbsup: If you scare, bring your notebook down to the shop that you buy the ram and ask if they allow to test before buy, normally they do and I bought my Twinmos ram from Fuwell and that guy was pretty helpful to make sure my system boot up and ram check properly.
As for the warranty void thing.....this is very gray....you have to read the clause.....I upgraded my IBM notebook's ram and harddisk myself and so far nothing bad happen...but I have intention to restore to the original should I need to send in for repair....so you need to see if there is any seal that prevent tampering before adding or removing the parts.