Upgrade cpu+mobo+ram or upgrade gfx card ?


Sep 24, 2011
i currently own a pc with

CPU Intel core2duo clocked at about 4ghz
Asus P5K-SE EPU mobo
4GB DDR2 800 ram
ASUS EAH 4890 DDR5 1gb

the systems heavy use is games (most demanding games atm : TDU2, BFBC2, CIV5, like to expand this with Skyrim and BF3)

i was thinking of upgrading with these :
Intel core I5 2500k (clockable, I7 performance diff is negligible for gaming)
MSI P67A-GD55 B3 (got great reviews, the z68 model i dont need)
4GB Kingston hyperx blu 1600 cl9 (8gb does not seem to be necessary for games so far, can upgrade later)

this costs about 400 euros, which is my budget atm

My question : would i gain most performance by buying and installing the parts mentioned above, or would i gain more performance by buying a new gfx card for about the same price ?

thanks for helping out if you please