Can i use the DIMM 1 slot A for this ram ? DIMM 0 A&B is with the 2GB pair
You can install that module into the DIMM, but it would not be recommended. The recommended practice is to install RAM modules in kits, such as the kit you have in DIMM 0.
Will it run in dual channel configuration ?
To achieve Dual Channel mode, the following conditions must be met:
Matched DIMM configuration in each channel
Same capacity (128MB, 256MB, 512MB, etc.)
Matched in both Channel A and Channel B memory channels
Populate symmetrical memory slots (Slot 0 or Slot 1)
Configurations that do not match the above conditions will revert to Single Channel mode.
The following conditions do not need to be met:
Same timing specifications
Same DDR speed
Memory channel speed is determined by the slowest DIMM module populated in the system.
Is it okey to combine 2 sizes of memory ?
You can, but you'll be limited to the lower specs of the combination.
My motherboard memory spec sheet says that it supports 16 GB maximum total system memory (with 2 Gb memory technology). What does that mean ?http://www.intel.com/support/motherboards/desktop/dh55hc/sb/CS-030953.htm
Thank you in Advance
It means that your mobo can support 4GB single sticks per slot.