Your ping in cmd should always be <1ms to the wifi router unless maybe you're using a wifi repeater or something similar. That being said I assume it is <1ms when you run win 7.
This article itself is a bit old but i found it useful from time to time. Especially read the part about DCA. Try changing some other settings there as well if you wish. You might get lucky!
Another thing that you could try out is to boot in safe mode with network and to do the cmd test. If it returns <1ms then boot normally and run 'msconfig' and select the default startup settings, then go to the task manager and disable all startup programs and restart. Try the cmd test again and if it's good start adding back programs until you find the one that causes the problem. Good luck!