XBMC buffering issues can be an annoyance while trying to watch a video on your HTPC. The problem amplifies if the video is of HD quality or if your HTPC has less available resources. Raspberry Pi, with only 512 MB of RAM and modest CPU power is prone to slow buffering. In this post, I will show you some ways to fix slow buffering on XBMC running on Raspberry Pi. These fixes should solve XBMC buffering problems in OpenELEC, Xbian, Raspbmc or a full-scale HTPC running XBMC. Note that some of the fixes for XBMC buffering issues listed below require XBMC 13 Gotham.

Source: Strategies to fix XBMC buffering issues on Raspberry Pi