So I've installed a few servers with the httpd rpm distributed by Parallels as part of 10.2 that has SNI support. Not sure what has been done in that one in comparison to the one from centos 5.6 but it reserves anywhere from four to ten times the memory.
Mem: 32938676k total, 24652480k used, 8286196k free, 1608220k buffers
Swap: 4192956k total, 119644k used, 4073312k free, 16220512k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
5409 mysql 15 0 2864m 1.8g 5312 S 6.0 5.6 927:22.59 mysqld
16840 apache 15 0 2682m 1.4g 4912 S 0.0 4.5 0:06.03 httpd
26371 apache 15 0 2682m 1.4g 4416 S 3.3 4.5 0:01.73 httpd
26373 apache 15 0 2682m 1.4g 4332 S 0.0 4.5 0:03.28 httpd
26405 apache 15 0 2682m 1.4g 4328 S 2.7 4.5 0:03.22 httpd
18128 apache 15 0 2680m 1.4g 4432 S 0.0 4.5 0:04.24 httpd
25212 apache 15 0 2681m 1.4g 3800 S 0.0 4.5 0:04.76 httpd
5946 root 18 0 2617m 1.4g 8680 S 2.7 4.5 0:37.47 httpd
It does this as soon as it starts so it's not some customer's php app causing the consumption. Same configuration with the centos httpd and it may consume 150 to 400 MB.
Mem: 32938676k total, 24652480k used, 8286196k free, 1608220k buffers
Swap: 4192956k total, 119644k used, 4073312k free, 16220512k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
5409 mysql 15 0 2864m 1.8g 5312 S 6.0 5.6 927:22.59 mysqld
16840 apache 15 0 2682m 1.4g 4912 S 0.0 4.5 0:06.03 httpd
26371 apache 15 0 2682m 1.4g 4416 S 3.3 4.5 0:01.73 httpd
26373 apache 15 0 2682m 1.4g 4332 S 0.0 4.5 0:03.28 httpd
26405 apache 15 0 2682m 1.4g 4328 S 2.7 4.5 0:03.22 httpd
18128 apache 15 0 2680m 1.4g 4432 S 0.0 4.5 0:04.24 httpd
25212 apache 15 0 2681m 1.4g 3800 S 0.0 4.5 0:04.76 httpd
5946 root 18 0 2617m 1.4g 8680 S 2.7 4.5 0:37.47 httpd
It does this as soon as it starts so it's not some customer's php app causing the consumption. Same configuration with the centos httpd and it may consume 150 to 400 MB.