memcached using 1.5x resident memory usage in dgm mode (4x including virtual memory)

top command results from cluster in amazon with 3 nodes where each vm has 8 GB RAM and each bucket is only 1.5 GB

as you can see memcached is using near 4 GB of RAM here and beam.smp is also using near 1 GB RAM

top - 05:57:49 up 5:19, 2 users, load average: 0.00, 0.01, 0.05
Tasks: 74 total, 1 running, 73 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.3%us, 0.3%sy, 0.0%ni, 98.9%id, 0.3%wa, 0.0%hi, 0.1%si, 0.0%st
Mem: 7652552k total, 7514356k used, 138196k free, 138272k buffers
Swap: 0k total, 0k used, 0k free, 4637816k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2029 membase 20 0 1107m 71m 2472 S 1.7 1.0 6:14.39 beam.smp
2069 membase 20 0 3159m 2.3g 3272 S 0.7 31.6 12:30.91 memcached
20473 root 20 0 14904 1080 824 R 0.3 0.0 0:00.23 top
1 root 20 0 19108 1280 1032 S 0.0 0.0 0:00.55 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:08.80 ksoftirqd/0
4 root RT 0 0 0 0 S 0.0 0.0 0:00.21 migration/0
5 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
6 root RT 0 0 0 0 S 0.0 0.0 0:00.14 migration/1
7 root 20 0 0 0 0 S 0.0 0.0 0:03.15 ksoftirqd/1
8 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/1
9 root 20 0 0 0 0 S 0.0 0.0 0:01.76 e