iMac late 09 memorry upgrade.

hi
i've purchased 16gb (4x4gb) placed imac (late 2009) , seems bottom slots wont take 4gb sticks. memory works fine , posts in top slots. beeps when place them in bottom 2 solts, original 2x2gb sticks work in slots.

on apples website state max memory 16gb, ideas?

in advance.

 

Forums Macs Desktops iMac

• iPhone
• Mac OS & System Software
• iPad
• Apple Watch
• Notebooks
• iTunes
• Apple ID
• iCloud
• Desktop Computers
• Apple Music
• Professional Applications
• iPod
• iWork
• Apple TV
• iLife
• Wireless