I have a HP_510 Pentium M 2.13 ghz, which have 1 slot for ram which came with 512 ddr. I want to upgrade to 1 gb of ram ,problem is I will have a wasted 512 if I buy 1gb of ram.So I thought if someone has a single 1gb of ram and two slots in their notebook and exchange for two x 512 ram. then it would work.Any other idea will be welcome.thanx 