better performance with 32 bit ! why?

[iharrathi.ext at orange-ftgroup.com]

Hi all,
I'm testing the same version of bind 9.4-ESV-R4-P1 on two server, one is a 32 bit (on which i have a redhat 32 bit) and the second a 64 bit server on which  i have a redhat 64 bit.
on the 32 bit i reach 70000 qps  but on the 64 bit i only reach 50000 qps (using resperf) and also with tcpreplay.

Is it normal that bind when compiled and installed on a 32 bit server have better performance than bind when compiled and installed on a 64 bit server.
the only différence between the two server is 64 bit vs 32 bit ( same RAM, same Disk, same NIC,...) and CPU is better on the 64 bit (2 Intel E5310 quad-core 1.6Ghz) than the 32 bit(2 Intel Xeon duad-core 2.33Ghz).

Thanks.

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