Your athlon 64 x2 4400+ has a passmark performance rating of 1149 and a single thread rating of 692.
It is the single thread rating that is most important for games.
Your proposed upgrades will have total passmark ratings in the3000-4000 range, mainly due to more threads.(games rarely can use more than 2-3 threads)
The single thread ratings will be in the 1000-1200 range, a nice upgrade.
But, consider that the cheapest intel skylake cpu, the $45 G3900 has a rating of 3381 and a single thread rating of 1711.
And, the integrated HD530 graphics on many skylake processors is about the same capability as your 6770.
Consider that it may be time to move to current tech.