Multiple WinTV Hauppage DVB-T Cards Hang, Single Always Work

[splurben]

I have a Linux system (Arch Linux x86_64 on Kernel 4.0.1-1-ARCH).

I have four WinTV Dual DVB-T Hauppage PCIe Cards:

• 2 x WinTV-HVR-1200 71999 LF Rev J3E9
• 1 x WinTV-HVR-1200 71939 LF Rev H2E9
• 1 x WinTV-HVR-1700 81519 LF Rev B2E9

All the cards function properly when installed individually.
The system always locks up if I put any combination of cards in the two PCIe slots I have available on my motherboard.
I don't know how to troubleshoot this. Is it likely to be something like a PCI latency issue or some such thing. I just don't have experience in this area.
Here's a link to output of # lspci -v http://pastebin.com/UUZDYA7b

[splurben]

Any help on this is greatly appreciated, thank you.