[PD] netsend in localhost --> i got "netsend blocked N msec"

[moritz]

ei lischt

i'm working with two pd instances on one computer (übüntü feischty, p4).
one pd with audio with higher priority, one with Gem/noaudio.
i communicate between this two instance with one netsend/netreceive and 
i send a lot of data, and sometimes i got "netsend blocked N msec".
is this a buffer-problem in the objects [netsend/netreceive]
or is there an intern bandwidth bottleneck?
or something else?

thanx for helping

moritZ