xlzhsteven :
I need to upgrade my laptop memory and is having two 2G memory in dual better or having single 4G memory better. I will have 2 x 1G extra, can I put 1G and 4G together to maximize the total ram ? (2 memory slot in my laptop)
Thank You
This completely depends on your Chipset and if it supports Dual Channel Memory and also if it supports more than 4GB of RAM.
If you max memory support is only 4GB & It supports Dual Channel Memory, 2 x 2GB is the best solution to max out your laptop.
If you Chipset supports more than 4GB, I would go with a Single 4GB Stick that way you can add more memory later.
What model is your laptop? That way we can look at the specs to see what it supports.