I'm having some issues with my iPad with Retina Display (a.k.a. iPad4).Overall, the device works well except for the WiFi connectivity can be terrible at times.
If the iPad has been on for any length of time, the Wi-Fi conneciton is terrible. It will take minutes to update my inbox, web pages will load very slowly and with no graphic elements. If I use the SpeedTest application, I'll usually get a pretty good downlaod speed that can saturate my Comcast Cable connection (Around 24Mbps), but the upload test will fail to show that any data was uploaded and of course will not give me an upload speed.
I can resolve the issue by simply rebooting the iPad. Once a reboot occurs, the device will perform as expected - which is lighting fast.
What I can figure out about this is it seems to be fine until it connects to another WiFi network. Once it switches to a new network (i.e. from home to work, work to home, home to Starbucks, etc...) the performance starts to suffer. It also starts to have performance issues if I go from LTE back to Wi-Fi. It's hard for me to beleive that this is at all network related as the issue resolves after a reboot of the device and it occurs with many different Wi-Fi networks in many different locations. In the case of home and work, I've got many different devices connected to the same APs that are not seeing any performance issues as this. (I am the network admin at my job, so I have full control and visibility into the WiFi networks at work). All networks are providing IP information via DHCP, and different DNS servers are in use at home, work, etc..
VZW LTE works fine whenever I use it. It's just WiFi. I have to beleive this is some type of software issue. I'm on iOS 6.0.1, which is the latest available for this device.
Any ideas, excluding basic networking troubleshooting (Again, all that has been tried...)