8590271648 :
Suggest me which part i change to play these games..
There a re a lot of games which will require a 64-bit setup. Don't know what your budget is but heres a setup. Changing one part might not be a option here.
LOW /MID BUDGET :
CPU - AMD FX 8350 / Intel i5 4690 (K if you overclock)
Mother board: 990fx series for AMD / H97 or Z97(newer) for the Intel
If you have a DDR2 RAM then you'll need 4 to 8 GB DDR3 (If you already use DDR3 then just add to it)
Windows 7/8 64-bit
GPU --> GTX 960 2GB / AMD 270x (AMD 280x if fits in budget)
PSU: IF Both CPU and GPU are AMD then 750 W else 550 to 650W
IF Both Intel then 500W would be more than enough
HIGH END:
CPU - Intel i7 4790k
Mother board: Z97 for the Intel (MSI Guard Pro is good and inexpensive)
8 GB DDR3 (Preferably at 1866 Mhz)
Windows 7/8 64-bit
GPU --> GTX 970 / GTX 980 / AMD 290x
PSU: 650 W for Intel+AMD, Else 550W enough for Intel+Nvidia
Hope This help is choosing the best.
P.S. SSD improves system boot and shut down times and the general OD Response. It is not necessary and is waste of money for home use. (Plus expensive, so if someone suggests, you can always buy that Later)