But Intel says that the i7-2620M supports up to 16GB of RAM. See it here.
I have asked for help on Toshiba Forums. Nothing useful from there. See it here.
I was curious as I have a very particular need for 16GB of RAM. Today I decided to give it a try. I bought two Patriot PSD38G13332S (8GB PC3 - 10600 1333MHz CL9 SoDimm) and installed it on the notebook. It just worked.
Bios screen showing 16384 MB of RAM.
Memtest86+ and some info about performance.
So if you have the need for 16GB of RAM and a similar notebook from Toshiba, you can install 16GB of RAM.