I run slip on a -current level machine.  The machine running slip reboots
at least once every two days and often once a day.  Another machine with
an identical kernel has been up for 10 days.  To test the theory of poor
hardware, I swapped the machines and produced identical results.

The machine running slip is unstable and exhibits reboots which do not
drop into DDB.  Frankly, I'm pleased it reboots and doesn't just hang 
likw 0.9 would.

In answer to your question, yes, there are serious problems with the
i386 slip.  You don't define 'very quickly' but I'm assuming you mean 
within a few minutes; I do not see that behaviour.

-john