A TEM and atom-probe (APFIM) survey of GP-zones and precipitate phases that occur in a 7108 Al-Zn-Mg-Zr age hardening alloy is presented, encompassing structure, composition and range of existence along the transformation paths during aging. Aging treatment included single-step aging at temperatures between RT and 150 degreesC, and double aging at 100degrees/150degreesC. Quenching temperatures were varied between 450 and 550 C. A structure model for the transformation: solid solution (alpha)--> GP(II) --> eta' --> eta-MgZn2 is shown. The connection between high solution temperature, GP(II)-zones and strength is discussed.