What could be the reason for the difference in memory consumption between an application on CentOS and Debian?

Question

Debian

There are two servers (Amazon instances): CentOS 6 and Debian Jessie. Both are running freeswitch built on the same servers from the source. Friswitch configs are the same.
top shows that freeswitch on centos takes about 2.5 gigs of virtual memory, while on debian it's only 850 MB:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
23243 dev 39 19 2380m 51m 9.9 m S 0.7 0.7 6:23.93 ./freeswitch -nc
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
729 dev 39 19 851092 43092 16752 S 0.8 4.2 5:03.27 /usr/local/freeswitch/bin/freeswitch - nc
Judging by pmap, the main difference in memory consumption is anonymous segments:
centos:paste.linux.chat/view/df8f192a (~2GB)
debian: paste.linux.chat/view/ba987a1e (~600MB)
Can someone explain to me why there is such a difference in memory consumption and is it possible to somehow then reduce its (consumption) on CentOS?
Freeswitch is built in the standard way (as written in its wiki): git clone, bootstrap, configure, make make install.

Answer 1

Judging by paste.linux.chat/view/df8f192a , I see that CentOS is 64-bit, but according to Deb I don’t see 32 or 64, what’s with Deb?