That's definitely at the low end of the specs for iTunes ... I have a Windows 8.1 notebook that has:
- AMD Dual Core C-50 1.0 GHz
- 4GB RAM
- Windows 8.1 64-bit
which it just about usable for iTunes as long as I'm not trying to run anything else significant at the same time - for example, playback will stutter or be interrupted if I'm running more than one browser window or other disc intensive processes like loading/saving a large MS Office document. That is with a moderately large iTunes library - another factor that can affect performance. Another factor in my case is whether I'm using the library on a local external drive, or connecting to one on my "master" system using Home Sharing. Performance is actually better in the latter case - I suspect that there's more extensive buffering over Home Sharing than there is using a slow-ish (USB 2.0) external drive.
Although I'm not using Airplay I do use this system - in either of its possible configurations - with Bluetooth audio (either portable speakers when I'm on the road, or a Bluetooth adapter hooked into my hi-fi system when I'm at home). This doesn't seem to be a problem, though obviously the Bluetooth link is dedicated device-to-device whereas Airplay is potentially competing for bandwidth on your wi-fi network.
You might want to check how your tablet functions with nothing but iTunes running, and maybe also try and reduce the number of background processes that start up with Windows.