Hi Justin,
What is the firmware version of the cards?
If it's not the latest, I recommend to upgrade to firmware version 2.9.1000 and use the latest WinOF 5.2 version that is the latest version for Windows 8.1.
You can find the proper firmware bin file in the following link:
http://www.mellanox.com/page/firmware_download
We did not test the latest driver with EOL ConnectX cards but we did not stop to support it.
BR,
Viki