I run watch dogs on max on my JZ. I overclock it with MSI afterburner. I run at +80 MHz for core clock, and +507 MHz for memory clock...
Just remember not to just jump to where im overclocking or you could damage the card. Start with +10 intervals, and if the drivers crash just move back -10 MHz until you find a stable clock speed.. but thats the stable clock speed i found for my card.. but once again everyone's card has different overclocking capabilities
SOO my card when playing watch dogs is at 1073 MHz and 3008 memory MHz
I get some lag here and there but most of he time its pretty smooth