Hai my system spec 4th gen i3-4150(3.5ghz),4gb ram,500 gb hdd,windows 8.1 64Bit,nvidia geforce gt 705 Ddr3 may i upgrade my gr

Solution
Yes you can always, depending on your budget, and go for a DDR5 version with DX11 graphics card to play modern day games.

Note : Most modern day games will demand 8GB of RAM, so you may need to add another 4GB of RAM also. Good luck.