Can't handle more then 2GB of RAM?

Heya,

I purchased some Kingston SO-DIMM DDR2 memory to upgrade my Mac MIni with. I purchased 2*2GB sticks hoping to have a total of 4GB in there and let the Mini use the 3.3GB or what ever figure it is that the firmware lets it see, but the machine won't post with more then 2GB in it at time.

Both sticks work, and both memory slots work, but they won't work at the same time. I tested 2*512MB sticks and that works but over 2GB and it doesn't post.

All the firmware is up-to-date and I can't think of anything else. Any suggestions?

Specs of Mac Mini
1.66CD
Airport
Superdrive
2GB RAM - hopefully 4GB

Cheers.