Performance of Bind 9.2.3 vs BIND 4.8.3

Hello All,
I want to upgrade from BIND 4.8.3 to BIND 9.2.3. For this reason, I am
doing a performance testing on the BIND 9.2.3 nameserver and the BIND
4.8.3 nameserver.

I am doing this by measuring the time taken between sending the query
from an application and recieving the response.

The test application is something like this:
start_time = curent_sys_time();
gethostbyname("myhost");
stop_time = curent_sys_time();

query_time = stop_time-start_time;

I am using the above piece of code to send queries to:
1) A BIND 9.2.3 nameserver and,
2) A BIND 4.8.3 nameserver
Both the nameservers run (not simultaneously) on the same system and
are not in any network.

I took about 50 readings for both nameservers.
The readings of this test reflect that the response time (the value of
query_time) in case of the 9.2.3 server is almost 50% more than the
4.8.3 server. i.e, a 50% performance degradation.

This is holding me from upgrading the DNS. I know that it may be
argued that BIND 9 provides security features -- etc. But, what is the
point when the most basic query processing is not very efficient?

As far as my understanding goes, BIND 9 servers are supposed to
perform better than BIND 4 servers, isn't it?

Any suggestions, clarifications are most welcome.

thnx in advance,
Nishant