Have not tried swapping cable, card,switch port yet.
Oddly slow network speeds between this system and any other with iperf. Doesn't matter if umfs10 is client or server - used these commands:

iperf -c umfs09 -i2 -t300 -w4M
iperf -s -w4M

Top speed on umfs09 is 3.43 Gbps. Top speed on any other client to any other server is ~7Gbps.
Myricom Diagnostics:

root@umfs10 ~/myri-pcie-tool-1.15a-linux# ./myrige-test.sh

Testing MYRI-10G NIC:   00:60:dd:47:53:09 (Internal loopback)
===========================================================

Turning loopback ON (was previously OFF)
Raw loopback test for 4 seconds:
[PASS] 33198 iters, 2124 MB, 4 sec, 4.034 Gb/s
Turning loopback OFF (was previously ON)

Ethtool -S eth2 (2008-04-01):

root@umfs10 ~# ethtool -S eth2
NIC statistics:
     rx_packets: 1595655
     tx_packets: 24914084
     rx_bytes: 2216554524
     tx_bytes: 139889511839
     rx_errors: 0
     tx_errors: 0
     rx_dropped: 0
     tx_dropped: 0
     multicast: 0
     collisions: 0
     rx_length_errors: 0
     rx_over_errors: 0
     rx_crc_errors: 0
     rx_frame_errors: 0
     rx_fifo_errors: 0
     rx_missed_errors: 0
     tx_aborted_errors: 0
     tx_carrier_errors: 0
     tx_fifo_errors: 0
     tx_heartbeat_errors: 0
     tx_window_errors: 0
     rx_skbs: 0
     alloc_order: 2
     builtin_fw: 0
     napi: 1
     tx_boundary: 4096
     WC: 2
     irq: 501
     MSI: 1
     MSIX: 0
     read_dma_bw_MBs: 1442
     write_dma_bw_MBs: 1736
     read_write_dma_bw_MBs: 2822
     serial_number: 325403
     watchdog_resets: 0
     link_changes: 6
     link_up: 1
     dropped_link_overflow: 0
     dropped_link_error_or_filtered: 926
     dropped_pause: 0
     dropped_bad_phy: 0
     dropped_bad_crc32: 0
     dropped_unicast_filtered: 926
     dropped_multicast_filtered: 3648
     dropped_runt: 0
     dropped_overrun: 0
     dropped_no_small_buffer: 0
     dropped_no_big_buffer: 0

-- BenMeekhof - 01 Apr 2008