I'm fairly certain this is a bug now. I've replicated the problem on another machine with a DH77KC motherboard, the card also autoconfigures as 1X there. In both systems, moving the card to the 16X slot causes successful autoconfiguration as 4X. This makes the video capture work perfectly, but at the cost of not being able to install a more powerful graphics card (not good at all).
I have also tested the card on an Intel DZ77SL motherboard. On this motherboard, there's no issue. Inserting the card into a 4X slot leads to autoconfiguration as a 4X card.
Here's a screenshot of the situation on the DH77KC when the card is inserted in the x4 slot, using x1 instead of x4. Video capture suffers from severe framedropping
When shifting the card to the x16 slot, the card successfully autodetects as x4. Video capture works perfectly
When inserting the card in a x4 slot on a DZ77SL motherboard, it autodetects correctly as x4.
If you're already updated the BIOS, I think you can't do anything more, and it clearly seems that it's a BIOS problem. Try to contact Intel Tech Support to fix this problem in next BIOS update. It seems Intel Tech Support don't read this, so you have to contact with them directly. Maintain the contact here to help other people with the same problem.
I Have the same situation
installing a Decklink HD 3D Extreme +
want 8 SATA ports
FireWire 800 on board or thru add on X1 card
X4 for Decklink capture card
X16 for Graphics card
what boards have you tried apart from the DH77KC
i was planning to get the DZ77GA-70K
any feedback would be appreciated
I've tested the card on two other boards, the one is an Intel DZ77SL motherboard, the other is a Mac Pro (2010 model) motherboard (according to Wikipedia, these have the Intel X58 chipset). In both cases, the card worked without issues. I'm not sure what this means re the motherboard you're interested in. It's chipset is in the same series as the DH77KC's, which may be worrying, but they seem to be very different from each other in terms of their support for PCI-e expansion cards
If my googling is correct, the DZ77SL
has the same chipset as the board you're considering (I only get hits for DZ77SL-50K, so I'm assuming this is the actual name for the other motherboard I tested, BIOS screenshot earlier in the thread). This seems encouraging.
Basically, before you buy it, I'd recommend finding out (in writing) if you can return the motherboard in case there's an incompatibility issue like this (If this happens, please post to this thread).
Currently I'm using my system without a 3D accelerator card, although this will have to change fairly soon. Haven't been able to conjure up Intel live-chat support (admittedly, I've been too busy to try continuously), and they seem to go out of their way not to reveal any way of e-mailing them about support issues. :/
I tried the following boards DZ77GA-70K and it works the BMD HD Extreme 3D + at X4
This board has integrated Firewire , 8 SATA Ports and suited my requirement
The Asus P8Z77 M Pro also works at X4 however this board is micro ATX and has fewer SATA and PCIe slots
I am now trying to optimise the speed of the capture ( 3D 1080p ) . get excess of 300 MB/sec on a raid 0
consisting of 4 Nos Seagate 1TB ES drive 7200 rpm : stripe size 128 KB / volume block size 64KB
using integrated Intel RAID SATA II