*There's a MAJOR PROBLEM with that PC.
The GPU (in the APU) requires fast DDR3 memory (i.e. 2133MHz CAS9) or it will be severely throttled. It's pretty linear so you're likely losing at least 40% of the gaming performance by using 1333MHz memory.
It's even WORSE by using a single stick so you could be under HALF the expected performance.
If it's a pre-built then there's nothing you can except to add another identical 4GB stick to help the bandwidth issue.
*If you are NOT committed to that machine then building with an inexpensive $80 to $100 AMD CPU and get an HD7750 or better graphics card would be a much better way IMO.
Other:
As per the comment ABOVE, I agree. AC4 and COD Ghosts are very demanding games and I don't think you'd enjoy playing them on that PC.
Probably not an option but PS4 would be far, far better than the APU system you mention, but my advice is BUILD at pcpartpicker for $600 to $700 if possible.