• You can't install 12GB as there are no 6GB RAM modules made.. So, you either install 8GB or 16GB of DDR3 or DDR3L...
• The "L" stands for Low Power and you can only install either regular or L but not mixed, and if you intend to buy "L" RAM, check what voltage they need and if the laptop bios supports it.
• The Lenovo G410 uses 1600Mhz RAM by default so better stick to that speed or check through a RAM website Configurator with auto scan to find the highest speed supported by your motherboard.
RAM Configurator search results.
http://www.google.com/?gfe_rd=cr&ei=SSuUU73jCImS8QfAjIGwCw#q=RAM+Configurator
16GB and 8GB Laptop RAM Kits.
http://www.amazon.com/s/ref=nb_sb_noss_1/180-5636372-3885150?url=search-alias%3Delectronics&field-keywords=16%20GB%20laptop%20ram