Home Built PC issues

[Nate13195]

My Friend built me a computer with the following spec, and im having issues with gameplay?
The majority of games dont play all too smoothly even when on the lowest of graphics settings, they just dont appear as smooth as console and have constant lag/tearing which is very annoying due the price of the computer, is there any reason why this is happening? eg parts, or settings? i already have all drivers i can get but im still facing issues, im open to any solutions even if it means replacing parts? thanks in advance guys

1TB Seagate ST31000524AS Barracuda

Samsung SH-224BB/RSMS 24x DVD±R, 8x

NZXT M59 Classic Series Black, Mid

Arctic Cooling Freezer 13 PRO Extre

21.5" Acer G226HQLBbd LED Full HD M

550W XFX Pro Series Core Edition P1

2GB XFX Radeon HD 7870 Core Edition

Intel Core i3 3220, S 1155, Ivy Bri

MSI B75A-G43, Intel B75, S 1155, DD

8GB (2x4GB) Corsair DDR3 Vengeance

Windows 7 ultimate edition

 

[Nate13195]

wrong mobo i meant to copy this one in 'Asus P8B75-M LE B75 MoBo'

 

[M-rod]

There's some things you can do to check if your system is running correctly:
1. go to the Bios and check everything is setup correctly, memory make sure that it is running at 1600mhz

2. this is not likely but it is a possibility that your processor is bottlenecking your system.

3.if your mobo has integrated graphics make sure that the gpu is installed correctly and conecting your monitor to the gpu not the mobo i think you may know this but
im just making sure

4.I may be wrong but i think your mobo is underpowered for your system and its probably bottlenecking it

other than that i have no other explanations as to why your having issues i hope this helped, and good luck!