Thats what the computer tech person told me to do, I figured I didn't have much to loose to try it his way, and it made since, Since i had no way of knowing if the grease would spread to cover all the die.
If it didn't work then I would just clean it off and try again, Since my temps dropped, I didn't worry about it. (i.e. I'm still using stock anyway).
Note: That even though I asked for arctic silver 5, I don't think that is what I got. as it looks pretty generic to me. But I wanted to clean out 2 years of dust and wanted to pull the cpu fan of to do so. so it didn't matter as much to me.