XAMPP's standard apache.conf isnt really set up for svn. It's memory usage grows and grows and will eventually blow up.
The default is
# ThreadsPerChild: constant number of worker threads in the server process
# MaxRequestsPerChild: maximum number of requests a server process serves
ThreadsPerChild 250
MaxRequestsPerChild 0
I change it to
ThreadsPerChild 64
MaxMemFree 100
MaxRequestsPerChild 0
Win32DisableAcceptEx
and everything seems to work fine.