New PC Gamer Needs Help Upgrading PC on a $325 Budget

[DiabeticManatee]

I have a HP p7-1054. I am switching to PC But I don't know much. I am thinking ASUS HD7790 but I don't know if its too much for my PC or could I do better for that price.
I also need a power supply I think of getting 650 W corsair. But I hear they have a problem with bussing noises and I get annoyed easily lol.
Should I even consider getting a new case.
Please give recommendation. Remember $325 dollar budget but it is flexible.
Game I wish to play - tomb raider, Bf3, Crysis 3(medium-high settings), SC2

 

[saikatbyte]

You may refer to
http://www.newegg.com/Product/Product.aspx?Item=N82E16814121686
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139045
http://www.newegg.com/Product/Product.aspx?Item=N82E16811139016
I think your motherboard is not reliable manufacturer, So you may later need to change it if you want stable gaming performance for future.

 

[tiny voices]

Motherboard has nothing to do with gaming performance at all.

Your case will be fine. Don't worry about getting a new one. Add one fan at the rear as an exhaust.

You should get a 500w PSU from antec, XFX, Corsair, Seasonic.


Here: PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: AMD Phenom II X6 1045T 2.7GHz 6-Core Processor ($107.13 @ TigerDirect)
Video Card: EVGA GeForce GTX 650 Ti Boost 1GB Video Card ($149.99 @ NCIX US)
Power Supply: XFX 550W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($54.99 @ NCIX US)
Total: $312.11
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-06-04 00:41 EDT-0400)

The reason for the phenom 2 x6 over the standard phenom 2 x4 965 BE is because your motherboard only supports 95w CPUs. Not 125w.