2.0-1649 rebalancing is two times slower than on 1.8.1-942( default bucket, 1M items, rebalance in 3 nodes)

compared 2 builds:
couchbase-server-1.8.1-942-rel and server-2.0.0-1649-rel

for testing used: ./testrunner -i FILE.ini get-logs=True -t rebalance.rebalancein.RebalanceInTests.rebalance_in_with_ops,nodes_in=3,replicas=1,items=1000000,max_verify=100000

configuration #1:
CentOS release 5.7/6GB RAM/4*2.6 CPU

2.0.0-1649 - 7min
http://qa.hq.northscale.net/view/All/job/andrei-rebalance-regressions/28/console
1.8.1-942-rel - 3min 40sec
http://qa.hq.northscale.net/view/All/job/andrei-rebalance-regressions/29/console

configuration #2:
Ubuntu 11.04/4GB RAM/4*2.6 CPU

2.0.0-1649 - 15min 50 sec
http://qa.hq.northscale.net/job/centos-64-2.0-rebalance-regressions/19/console
1.8.1-942-rel - 7min 40 sec
http://qa.hq.northscale.net/job/centos-64-2.0-rebalance-regressions/20/console