can early 2008 use 16 GB of memory? does someone knows

Maximum Memory 6.0 GB (Actual) 4.0 GB (Apple)

Memory Slots 2 - 200-pin PC2-6400 (800MHz) DDR2 SO-DIMM

•How to remove or install memory in iMac:

http://support.apple.com/kb/HT1423

The older models are like that... with their repective system

demands & associated applications... did OK in their day.

For some, an upgrade to the latest supported OS X may

be a stretch however, so be aware of consequences there.

Later RAM upgrade specs that show a higher ceiling

of supported installed chip capacity can be found at

sites such as everymac.com or database download

from mactracker.ca for certain model variances.

Good luck & happy computing! 🙂