PC5300 DDR2-667 RAM stick designed for DDR2 motherboards only.
Current Macs that take PC5300 SO-DIMMs are:
PC5300 = Intel based products (Jan/Feb, May, Sept & Oct 06)
All MacBook Pro 15" & 17", MacBook 13.3"
iMac Intel Core Duo 1.83GHz and 2GHz, MacMini Intel Core Solo 1.5GHz & Duo 1.66GHz
iMac Intel Core 2 Duo 1.83GHz, 2GHz, 2.16GHz and 2.33GHz (Sept 06)
MacMini Intel Core Duo 1.66GHz & 1.83GHz (Sept 06)