odd sparc behavior

[ken]

I've have 3.0r0 stable installed on two sparc ultra 5's. These are the 
newer
ones...336mhz I believe. What I'm dealing with is that when I'm ssh'd 
in,
both of them will hang sometimes for about 30 seconds or so. If I leave 
a
term alone for a few minutes and go back to it, it's just dead for those
few seconds then comes back to life. I know this has nothing to do with
my network as I have several x86 boxen that work fine on the same seg.
Anyone seen this before?