NDB Performance (no replies)

I have a very simple cluster setup.

Host A - Management Node
Host B - Mysqld + NDB1
Host C - NDB2

The setup seems to work fine other than the speed of queries is noticeably slow when NDB2 is running on the second node.

My testing finds the following
NDB1 up , NDB2 up = slow
NDB1 up , NDB2 down = fast
NDB1 down , NDB2 up = slow

It's clearly something to do with the MySQL process communicating over the network.

Are there any parameters / configuration that might help this.

My sample query involves left joining a number of tables (about 6). This allows me to see the latency clearly.

Any help would be gratefully appreciated in advance.

Jonathan