Tom,
Here are the ConnectX-3 QDR cards and their descriptions.
| MCX353A-QCBT | ConnectX®-3 VPI adapter card, single-port QSFP, QDR IB (40Gb/s) and 10GbE, PCIe3.0 x8 8GT/s, tall bracket, RoHS R6 |
| MCX354A-QCBT | ConnectX®-3 VPI adapter card, dual-port QSFP, QDR IB (40Gb/s) and 10GbE, PCIe3.0 x8 8GT/s, tall bracket, RoHS R6 |
If you have one of these two cards, the Ethernet speed will only work at 10GbE.
Anand