Hey Dave, a couple of things before I/we can help.
1) What's your budget? Because of this, I can't make too many suggestions.
2) What games? In gaming, the graphics card is most important, followed by the CPU.
2 Small inefficiencies:
1) The Asus GTX 660 TI 2GB has a PCIE 3x16 interface, whilst your GA-78 LMT has a interface of 2x16.
Your motherboard can not harness the full potential of the full potential transfer rate.
2) The Corsair Vengeance 8GB 1600 has a speed of 1600mhz, whilst your motherboard only has 1333mhz.
This means your RAM will be running at 1333mhz instead of 1600mhz.
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- BUT It isn't the end of the world, it just means that they won't be running at the highest speeds. It should be running fine, nothing overly significant. I wouldn't be too worried but I just wanted to give you the information you would need.
- It will run fine, sometimes even the latest and higher end graphics cards can't fully utilize the PCIE 3x16
- IN SUM, FX 6300 is a great card for it's money, and so is the GTX 660 TI 2GB.
- If you want to 100 dollar more expensive build, you can get an Intel Core i5 processor a slightly more costly motherboard.