Slow VCL speeds

As a continuation of this thread, I've got updates...

I'm now running:

Broker- 1U server, 12GB RAM, Mellanox ConnectX-3 QDR Infiniband HCA connected directly to other HCA (running opensm), oclhashcat 1.0, VCL1.22

Node- 7990, 6970, Mellanox ConnectX-3 QDR Infiniband HCA

I've updated both HCAs to the latest firmware; all modules are loaded, ping works, oclhashcat detects the 3 GPUs and works, but...

SLOW!!! I'm still only getting ~50% of what I get with the machine running standalone.

The HCAs are running in connected mode, and I've tried MTUs of 2044 and 65520.

Ideas? I'm very frustrated.

Thanks!

EDIT- forgot to mention that eth0 is on 192.168.10.x and ib0 is on 10.10.10.x...