Understand that I necroposter, but he has recently faced with this problem, so I decided to unsubscribe for future generations :)
The situation is similar as the author, MacMini late 2009 with 4 GB of memory, it is necessary to expand to 8.
What relatives die standing Kingston 1333D3S9/2G two pieces. As can be seen from the labeling, it is a memory PC3‑10600, although in Speke on the website Epple stated maximum PC3‑8500. Ie they put not supported. No matter how it sounded.
Bought KVR13S9S8/4 two pieces - didn't take off either together or one at a time. Although the same PC3‑10600 as the native.
Exchanged for Transcend Jetram (JM1066KSN-4G) is turned on. Sees all 8 gig of memory.
Thus, somewhat surprisingly, memory PC3‑10600 only works with the volume bar in 2giga, 4 already does not start. Memory is PC3‑8500 works fine.