16GB of RAM makes MacBook Pro's fans go wild before sleep? I recently: 


installed 16 GB of RAM (1600 MHz);
on my late-2011 15-inch MacBook Pro; 
running OS X 10.7, aka Lion;
with an Apple SSD drive.


According to Apple my MacBook Pro only supports a maximum of 8 GB at 1333 MHz, but the chipset supports more (both GB and MHz) — but I'm aware that it does not mean it'll actually be compatible with my machine.



The problem:

Whenever I put the laptop to sleep (by closing it), it takes a while, and the fans start spinning very loudly before the computer finally reaches sleep mode.

The reason is likely to be Safe Sleep — but why are the fans going crazy?

Is there something wrong with my Mac? 

How do I prevent this without disabling Safe Sleep?

Would updating to OS X 10.8, Mountain Lion, help?
That is normal function. 
It is called air vent (power air purge), to remove the residual heat before shutting down (or sleep mode).

It is meant to prolong the life of your devices.

The designers have figured out that by shutting a hot computer down, since there is no ventilation the heat actually rises inside. 
That is not so good for the computer so someone had the bright idea to do the air purge before shutting down. :)

However! one should say that you are running your computer at the "Borderline" (hehe) of capacity for cooling since you stuffed it up with more heating sources.