Thank you so much Cliff S :) , bobkn :) and spunk :) for your valuable information. I will go for 8GB ram very soon.

My Motherboard is - Gigabyte H55M-D2H,
Processor - Intel Cor i3 (2.93Ghz)
Using Windows 10 pro 64 bit.
My current ram is 4GB ddr3 1333mhz (2gb * 2).
Will my system support 8GB ddr3 1333mhz (4gb *...