CrazyMan3820, you need to do a LOT more reading and get to a different level of understanding... Your fund of knowledge is in conflict with everyday use...
Methinks you misunderstand what a power supply does and how it does it; what a videocard means to a gamer install and why; and what good memory means to the gaming computer.
For you to count on the 8400 video card and miss the part about memory, means that you are perhaps losing out on some real fun at your computer.
First thing most important is CPU, and CPU cooling... and the difference between a Celeron and a full CPU and why. Second is MEMORY... high speed, high perforformance memory.... not valueram... and not just install ing half of what you need; Third is quality in components vs average components.
Suggest you get some good gaming magazines and read everything you can find on gaming sites and bring yourself up to speed... because it will be difficult for the experts on this forum to give you good advice at your current level.
I mean no offense by this, but offer this suggestion to hopefully offer you more fun through gaming.