I m thinking to use mx 4 for my cpu and gpu , bcoz i tot the paste can last very long ,no need to reapply so soon . But after got ur experience with mx4 , may change my mind to buy it.

"Warning: Please note that you can’t use the Coollaboratory Liquid Ultra with a contact area of aluminum, as it corrodes aluminum. The heatspreader of actual processors consists of nickel-plated copper, not of aluminum. Advice: The application on copper surfaces is a bit easier than on nickelplated ones, but possible is both."