Z77 Pro3, Pro4 PCIE2 port doesn't work

It seems that there is a problem with the Z77 chipset with some boards that caused the system to fail to recognize PCIE 3.0 GPUs unless the slot is set to gen 1 or 2 though I see that the OP has already tried that solution. All I can think of trying is clear CMOS and set the slot to gen 1 and try it again. Oh, additionally, if it is the same problem I found when I searched this then a gen 1/2 GPU should still work fine in the slot so it may be worth while finding an old Gen 1 or 2 card to try. If that fails too then the slot must be dead in which case you will likely need to replace the board 

Steiner06 wrote: Hi guys, i have exactly the same issue as Bigmatt.  My Setup is: - Z77 Pro 4 - I5 2500K CPU - 2x4 GB Corsair XMS3 - PSU: OCZ 600W 80+ / Model OCZ600MXSP  - Samsung SSD 840 Evo 500GB - Gigabyte GTX 970 G1 Gaming  the gpu is only running in the PCIE3 Slot with of course only 4 lanes. When i put the GTX 970 in the PCIE2 Slot even if i change it manuly to Gen 1 or Gen 2 doesnt matter i get a black screen but the pc in the background is booting fine. Even in the system browser in the UEFI there is no card detected, so i have to use the onboard GFX to get a picture in UEFI Bios. I tested every BIOS Setting combination possible on the Northbridge page, without success :( The GTX 970 works flawlessly in a computer from my buddy, but he has a z97 board. is there a workaround? sry for my bad english ;)

Your English is very good, I can understand you fine.

Given this information, and that of the OP, it seems like an incompatibility issue that would need a UEFI/BIOS update.

Not that this is directly related to the problem, let's look at the specs for the PCI Express slots on this board:

- 1 x PCI Express 3.0 x16 slot (PCIE2: x16 mode)

- 1 x PCI Express 2.0 x16 slot (PCIE3: x4 mode)

PCIe Gen3 is supported on 3^rd Generation of Intel^® Core i5 and Core i7 CPUs.

Notice that the PCIE3 slot is PCIe 2.0, which is provided by the Z77 chipset.

The PCIE2 slot's lanes are provided by the CPU, not the Z77 chipset. Sandy Bridge processors only provide PCIe 2.0 speed lanes (16), and Ivy Bridge processors provide PCIe 3.0 speed lanes (16.)

Bigmatt also uses a Sandy Bridge processor (i7-2600K.) Both Bigmatt and Steiner06 tried using new video cards, released a few years after this board was new. I'm not saying those cards cannot be used with this board, they should be but it looks like a UEFI/BIOS patch will be necessary.

You can try this, but I cannot guarantee it will work:

With the PC shutdown and the power supply turned off and unplugged, disconnect all video cables from the video card and the integrated graphics outputs. Clear the CMOS/BIOS with the jumper on the board. I want to suggest removing the CMOS battery to do a complete CMOS clear, but the battery will be under the video card.

Connect your monitor to only one of the integrated graphics outputs, with no other cables connected to the video card or integrated graphics outputs. (If you are using a VGA (analog) cable, meaning not a DVI or HDMI (both digital) cable, that might be part of the problem.) Connect power to the power supply, and start up the PC. You should be prompted to go into the UEFI/BIOS after the CMOS clear, which I want you to do right away, don't boot into Windows.

In the BIOS, on the Exit screen, click the Load UEFI Defaults button. Then set any BIOS settings you must have if you use them, like RAID, etc. Do not OC the CPU or memory.

Go to the Northbridge Configuration screen, and check or set all the following options:

Set PCIE 2 Link Speed to Gen 2.

Set Share Memory to Auto.

Set IGPU Multi-Monitor to Disabled.

Set Render Standby and Deep Render Standby (if you have this option) to Enabled.

Notice that I did not mention the Primary Graphics Adapter option. I want it set to PCI Express, which it should be by default.
Finally, Save and Exit, and boot into Windows. You can check in Device Manager if the video card is listed in Display Adapters. If it is, open its Properties to see if the device is Ok.

Even if you don't see the video card in Device Manager, shutdown the PC and remove power. Disconnect the video cable from the integrated graphics and connect it to the video card. Just use one video cable to one monitor. Connect power to the PC, start it up, and see what happens.

Let us know what happens, either good or bad. If you experiment further, the options I listed above, except Primary Graphics Adapter, should be set to what I listed.

Steiner06 wrote: Thanks for the reply parsec i tested what you suggest but without success. I even downgrade the UEFI Bios to all available versions but there is no way i can get this card running in the PCIE2 Slot.  I tried to deactivate the onboard USB 3.0 / LAN / Audio controller to get the lanes from the cpu free, but even that makes no differents.  I'm running out of ideas :(

Neither I can test my config with a gen3 CPU as I am not going to buy one just to find out whether it solve my issue or not. We are on the same page with Steiner, even if our CPU is only Gen2 there is still a lot of juice in these and easily can handle the current programs/games. I am not planning to upgrade the CPU, just simply not worth it for the moment.

I also tested what Parsec suggested, but everything is still the same...
Steiner 06 - So the Gen2 GPUs is working for you? That's interesting becuse no matter which Gen GPU I try to use neither of them is recognized by UEFI system browser or Windows.

Parsec - As you have mentioned a BIOS update would be necessary. I know that this is an older MB, but we would really appreciate if someone could work this out for us. I do think that Asrock is a great company and you care about the small people like us as well. When I got back my money after I returned the Pro3 MB I purchased an Asrock MB again because I think that this is a great product, please do not let me to get dissappointed, thanks in advance.

I currently have the same issue with an MSI R9 280X 3GB twin frozr