why gta IV running bad on my pc ?

Lucifer himself

Commendable
Jul 23, 2016
80
0
1,640
my pc spec. :
CPU : Xeon w3565
GPU : Zotac gtx 950 amp 2gb
Ram : 12 GB

Game setting :
game setting res : 1440x900 65MHZ
Texture quality : High
Render Quality : High
View Distance : 1
Detail Distance : 50
Vehicle Denisty : 35
Shadow Denisty: 10

i run it on not more than 60FPS and sometimes it droped to 43FPS !

the funny thing that i can run arkham origins that has better graphics than gta iv and it also
released after 5 years from gta iv realeasing
i can run arkham origins on not less than 60 and not more than 124FPS , the avg 75-80 FPS in ultra and Dx11 Enhanced without antialising,.. while i run gta iv on not more than 60FPS and not less than 40FPS on medium-low

so how to fix it ? is gta iv poor optimized ?
and if i run GTA V this time will i get +60 FPS ?