Z790 Hero not running GPU as PCIE 4.0 X16 but 3.0 instead

[Raigoz]

So got a new build with Z790 Hero paired with a 13700k and GTX 3080 12GB and I noticed with GPUz it says gpu supports up to PCIE x16 4.0 but its running at x16 3.0.

I went into the bios and selected Gen 4 on PCIE but no change gpu is in the top socket on the board.

Any suggestions would be appreciated.

[pcgamersz]

same problem with same mobo and 13900kf and rtx 4090 strix oc but nobody helps.

[Hurtzrus]

It’s because you will have an SSD drive in the top slot. You cannot put it in M.2_1 socket move to the lower ones or the ROG Hyper Card and ensure you turn it on in the BIOS if you use it. Leaving the Top SSD card empty with put you onto Gen4, not sure why they set it up like this but SSD works fine in any of the other two onboard and the HyperCard leaving the channels for the Graphics card which I had the same issue and now runs at Gen 4

[pcgamersz]

its probably the asus trash mobo hero z790..never buying asus again

[Nate152]

Yeah it should be x16, reseating the gpu will likely fix this.

[pcgamersz]

reseat the gpu did not fix..

my friend believes its a bios bug but even if i downgrade to previous 1202 its not fixing it.

[Hurtzrus]

It’s because you will have an SSD drive in the top slot. You cannot put it in M.2_1 socket move to the lower ones or the ROG Hyper Card and ensure you turn it on in the BIOS if you use it. Leaving the Top SSD card empty with put you onto Gen4, not sure why they set it up like this but SSD works fine in any of the other two onboard and the HyperCard leaving the channels for the Graphics card which I had the same issue and now runs at Gen 4. Check with GPU-Z after moving about and you will see it is Gen 4 and make sure you set the BIOS to GEN4

[Nate152]

Actually, you can install your ssd in the M.2_1 slot and still have your gpu run at x16 as Alderlake/Raptorlake cpu's have 20 pcie 4.0 lanes or 16 pcie 5.0 lanes.

Remove the ROG Hyper M.2 card if you have it installed.

I'm personally running an ssd in the M.2_1 slot (x4) with my RTX 3090 ti at x16 on the ROG Strix Z690-F Gaming Wifi. I set both link speeds to Gen 4. 

Then start a game and see if your RTX 4090 ramps up to pcie x16 4.0

[pcgamersz]

not using rog hyper...im gonna take the gpu tomorrow and test it on another machine...the problem became worse when i went with 1303 latest bios... before i had 16x3.0 and than i though 1303 is gonna fix that and it made it worse...looks like im not alone tho other people ahve the same issue with HERO z790.

[Nate152]

Do you by chance have anything installed in the second pcie x16 slot? If so, this will drop your gpu to x8.

You could try clearing the cmos again or enter the bios and hit the F5 key to reset to defaults.

If nothing is helping, then testing your gpu in another pc is a great idea, I'd like to hear the results. Make sure the power supply in the other pc is strong enough for your RTX 4090.