Your friend is right. If you get the same brand/type, you should'nt run into compatibility problems.
You can buy a different brand/type but make sure you get something with the same timings or slower timings. All 4 dimms will be running at the same timings and same voltage (at least on my...
I currently have a 1 gig kit (2x512) of ddr4 OCZ platinum rev2 going at 2-2-2-5 at 2.75 volts.
http://www.ocztechnology.com/products/memory/ocz_el_ddr_pc_3200_dual_channel_platinum_rev_2
I want to add another 1 gig in my computer but I can't find this ram anywhere in Canada anymore.
So I...