High mem usage

[Dmitry Rybin]

FreeBSD 5.5, bind 9.4.1 without threads and with 
ISC_MEM_USE_INTERNAL_MALLOC=1

named eat memory over 1gb and begin to use 100% CPU. Can I limit memory 
usage (as in djbdns) or may be tuning tips?

=== named.conf ===
max-cache-size 256M;
===