Sorry but your CPU is way too weak even to couple with a low grade GPU from this recent generation. If your CPU can't provide enough muscle, your money spent on GPU will be wasted. And your CPU can't do that. I can't debate on that but probably your CPU will hold back around half your GPU's performance (maybe more, i can't say exactly), especially if it is a 660ti. Best way would be to balance your budget and get a decent CPU and GPU. I can't debate on your PSU either cause i don't know what brand/make it is, use it at your own risk.