Ram for HP Pavilion DV2120US Vista

My computer's ram speed is 533 mhz and has two 512mb sticks with Windows Vista. Can I replace one of the sticks with a 667 1 gb stick? Will it then function as a 1.5gb 533mhz ram? Also, if the ram sticks are of different sizes (512mb v. 1gb), then does that prevent it from running in dual channel?

Thank you in advance!

You can take a look at the following,

• LINK

Hi SHINMA,

I looked at that web page before posting but it does not answer my questions. Does dual channel force consumers to buy 2 of the same size ram sticks? Can I just leave one of the old sticks there and just buy a new one?

http://www.answers.com/topic/dual-channel-architecture