Ping to the router is normal (1ms)
Ping to google or my isp isn't great (approx 90ms) but then my dslam is far from my home so this looks normal.
From my wired ethernet connextion, ping is 30ms lower.
It doesn't vary when resuming from standby or when on battery. The box to allow the computer to turn off the device to save power is unticked.
I'm going to tick it to see if it changes anything.
As far as I'm concerned this problem is solved (Dell Inspiron 1720 x64 - Win 8.1).
Well I am not sure for how long you did the test. Here at home my WiFi connection seems to drop/delay a couple of packages every couple of minutes. At work on busy WiFi it was actually impossible to get a stable connection for more than 30 seconds while my
other laptop placed right next to it would just not drop any packet.
Sounds a bit strange that your wired connection is 30ms lower while wifi connection to router is 1ms or lower. The only explanation to this is the router forwarding packages delayed. Anyway, we are not here to debug internet connections, ISPs or routers.
So you also disabled the option to turn off the device to save power in device manager.
Well for what concerns the WiFi connection here at home it looks fine for me as well. But I have to find out why at work it's not working properly and dropping a lot of packages. I was playing with 802.11n mode to be enabled/disabled at no avail.
In any case the issue is not solved for me by using an outdated driver and disabling power management. It is solved when Microsoft fixes the kernel not to BSOD and/or Intel/Microsoft will release a fixed official driver which properly supports power management.