RAM issue with Gigabyte X58A UD3R

[za man]

My problem is that i own 4 memory sticks 4x4 with the total of 16GB when i try to use channel A alone my PC is not booting although the memory sticks are fine as when i use the same sticks in channels B & C the PC boots with no problem.

If i mixed the RAM sticks in different channels it only reads the sticks in channels B & C although it shows in the BIOS like in the pictures below in channel A but not calculated in the total RAM size i am afraid i am doing something wrong.

any help is appreciated.

PC configuration:
i7 950 3.06GHZ 8MB cache quad core
Gigabyte X58A UD3R rev.2  Bios FH
Kingston 4x4 KVR1333D3N9 V1.5
GTX560 Ti 1024MB  GDDR5
PSU Cooler Master 500Watt
Case G-Lite Elite 310
Western Digital 1TB Green
DVD Asus 48X
  

[autotech]

On your board it says for those memory modules only 1 or 2 gig sticks should be used. The 4 gig sticks are not certified for that motherboard.

[za man]

First let me thank you for your reply but in case my RAM stick module is not supported by the motherboard why when i install the RAM sticks in channels B & C it runs perfectly?