Thanks for taking the time to test and reply guys

chispy

I have noticed that your card is running @ x4 Gen 2.0. Have you by any chance got dirt on the slots or the card? Or are you running Tri SLi or something?!?

It is unusual to see an nForce 790 based motherboard exhibit such a strange problem.

Chickenfeed
Ahh thanks for that, this would explain the card and slot mismatch on your GPU-Z screenshot. A PCI-E 2.0 card running on a PCI-E 1.1 slot. I have not heard about some boards being PCI-E 2.0, however what you say would make sense if they were very late production models out at the same time as the X38 and X48 boards, but just before the P45 was released?!

Thanks for the information overclocking101
Similar behaviour has been noticed on a ASUS Maximus III Extreme, however that was running PCI-E Gen 1.1 with just one card in the system (@ x16) and then x8 with two cards in the system. Perhaps your eVGA board is half fixed?

I would keep an eye out for BIOS updates.

As far as I am aware P45 boards are immune to this issue, however if any P45 readers are out there, please do provide screenshots confirming or contradicting what we have found so far with P45 boards. Anymore X38 and X48 users will be most welcome..

Thanks

John