Upgrade the Mac Mini 2011 to 16GB of RAM for $70

As the wikipedia page on the Mac Mini indicates, the 2011 (and apparently the 2010) model can handle 16GB of RAM.  When it was introduced, 16GB of DDR3 RAM was more expensive as the Mac Mini itself.  But these days, you can get 16GB (2 X 8GB) DDR3 SO-DIMMS for well under $80.  I just bought some Patriot RAM from Fry's for $59.  I also just got AData SO-DIMMS from Newegg for $65.

The main constraints on the maximum RAM a system can use are

1. the maximum RAM the CPU can address.  For Intel CPUs, see ark.intel.com.   It is sometimes tricky to determine the actual CPU your system has.  In the case of the 2011 MacMini, the i5-2410M CPU can handle upto 16GB via 2 DIMMS or "channels".
2. the address lines on the motherboard M/B.  In most cases, the M/B carries all the address lines from the CPU to the DIMMs.
3. the manufacterer's BIOS or EFI, when booting Windows.  I'm fairly sure Linux probes the hardware itself so even if the BIOS underreported the amount of RAM, Linux would detect it all.

The speed of the RAM is not terribly important, except under very rare circumstances, in which case you'll know who you are.  For perspective, faster RAM might get you 1-2%; having more RAM so you do not  swapping will get you a 400-2000% improvement.   Also, DIMMs contain information on their speed and the memory controller will adjust accordingly.  

I usually just buy what is cheap from a decent brand (Crucial, Patriot, AData, ....).