Here are my specs :
motherboard : Ashrock M3A790GXH128M
processor : Phenom II x3 710
memory : KVR1333D3N9K2/2G (2 sticks of 1GB) in Dual Channel
OS : Windows 7 x64

No question, I need more RAM :
** I would rather prefer to save 2 slots for future needs and - as a price dropped down lately - buy now 2 x 4GB sticks of Kingston 8 GB / 1333 (2x 4 GB), CL9 ( KVR1333D3N9K2/8G ).
** But I read about some problems with bigger (more than 2GB) sticks. Therefore I consider also more safe option : buying just 2x2GB , probably Kingston 4 GB / 1333 (2x 2 GB), CL9 ( KVR1333D3N9K2/4G ).
** And what about using these new 2x2GB together with the old 2x1GB (the same make and type of memory) ??
** Generally speaking : Is 4x2GB better configuration than 2x4GB ?

The problem is that Memory QVL for my motherboard shows as compatibile only memory sticks up to 2GB, so it can`t help me to chose...

Could you please answer my questions and advise what memory should be optimal choice in my case ?
If you think Kingston isn`t the right choice (tight budget and no OC) - suggest another make, please.

Thank you in advance for your assistance..