RB1100AHx2
how much memory can be installed in the router?
4 GB can be?
Why you are asking instead reading product specification page??
http://routerboard.com/RB1100AHx2
What is unclear in the product brochure?
http://i.mt.lv/routerboard/files/RB1100AHx2.pdf
SODIMM DDR Slot, 2GB installed (RouterOS will use only up to 1.5GB)
This means that the OS version will not be any use?
This is a hardware limitation or software?
yes 