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Z790 Hero - M.2 configuration with a RTX 4090

Level 9

Wanted to make sure that I understood this correctly. If my goal is to have the RTX 4090 run at x16 and my M.2 drives to run at x4; I could do the following.....

1) Install 4090 into the PCIEX16(G5)_1 slot - And get x16
2) Install a boot drive Gen 4 SSD into the CPU Lane driven M.2_1 Socket - And get x4 with no impact to the gpu
3) Install a storage drive into the chipset driven M.2_2 Socket - Get gen 4 speeds with no impact to the gpu
4) Install a storage drive into the chipset driven M.2_3 Socket - Get gen 4 speeds with no impact to the gpu

This should get me all the storage that I need as I do not have any interest in using the ROG Hyper Card at this time.

I appreciate the help


Level 9

Just an update in case someone comes along this thread and is curious; new board solved the problem handily. Guess my first one was just a lemon. First bit of properly defective hardware in 10+ years of building rigs. Bit of a shame but it happens.

Update on this since I saw someone give this message kudos and the situation has changed since; it would appear that no, the board was not defective, it was just a very, very odd BIOS bug. Same thing happened with my new board after a few months, and I remembered something I had came across after having it replaced. Someone mentioned that changing a setting for the expansion slot to 'Dual Optane Memory' somehow forced the top PCIE slot back into 16x 4.0...and it worked, and was repeatable. 

Why on Earth this board randomly decides to bifurcate the top slot even when it shouldn't, and why that bifurcation cannot be stopped ANY other way, including clearing CMOS, is beyond me, but this worked. Sadly I didn't find out till ASUS's incompetence wasted a LOT of my time. 

13900KS / Z790 HERO / 64GB 6400MHz C32 / 4090 FE

Level 17
I have a Z690 Hero, and with 3x NVME drives on the motherboard (two are Gen 4) I am still getting 16x for the GPU. No problems for me. My setup is:

NVME Gen 4 in slot 2_1
NVME Gen 3 in slot 2_2
NVME Gen 4 in slot 2_3

I didn't plan that setup, think I just got lucky lol
Z690 Hero, BIOS 3401, MEI 2406.5.5.0, ME Firmware, 7000X Case, RM1000x PSU, i9 12900K, ASUS TUF OC 3090TI, 2 x 16GB Corsair RAM @ 5200MHz, Windows 11 Pro 23H2, Corsair H150i Elite AIO, 4x Corsair RGB fans, 3x M.2 NVME drives, 2x SATA SSDs, 2x SATA HDs.

Level 11
So i wanted a motherboard that i can use M.2 slot between cpu and gpu, and still get x16 with my 4090, and it seems this hero does that, but i dont want to spend almost £700, whats really strange is, the much cheaper ASUS ROG STRIX Z790-E, cant do it, it drops to x8, because the M.2 slot is gen 5 on that board, and only gen 4 on the expensive hero, why is this ?

Level 7

 This is exactly how I am planning my new build as well:

  • PCIEX16(G5)_1 - EVGA 3080 TI Ultra Gaming FTW3 @ 16x
  • M.2_1 - NVME SSD for windows @ 4x
  • M.2_2 - NVME SSD for games @ 4x
  • M.2_3 - NVME SSD for data/etc @ 4x

From reading this entire thread, this is possible on the Asus z790 ROG Maximus Hero board.

Bye Bye mechanical drives, and SATA SSD's.  Hello ZOOM ZOOM.

Level 9

Hello, for everyone with the same Problem, if you install a pcie4 ssd on every place there should be no Problem with the first PCIe slot for the gpu only when using a pcie5 ssd than you will get lower pcie5 conection.... Istalling a pcie5 m. 2 you will go down from PCIe"5" x16 to PCIe"5"x8 on your gpu Port



And even when you get a impact with all pcie4 m. 2 ssd this is on pcie5 Not pcie4, every gpu right now ist connected with Max pcie4 x16

My Asus z690 apex is populates completly with pcie4 m. 2 ssds and the gpu still runs with pcie4x16 that is the max conection for nvidia 4090

People don't use M.2_1 gen4 and a 4090 for full speed. Too many people with other platforms chiming in on something they don't own. Asus had some bad documentation in the manual. 

Level 7

Just picked up my Z790 Hero, 4090 GPU and was planning (bought already unfortunately) a Gen 5 SSD for Slot 1 and two gen 4’s for Slot 2 and 3. 
Now I realize I can only install the Gen 5 in the riser card which will throttle both the GPU and SSD to x8. 
I bought the Hero cos I saw it supported Gen 5 SSD’s but that’s misleading if you can’t use it at its peak together with the GPU. 
so now my question is : can I install my Gen 5 SSD in slot 1 and will it just run at Gen 4 speeds? 
What will give more of a performance hit? Running the GPU and SSD at x8 or GPU at x16 and SSD slower? 
I read somewhere that 4090’s don’t perform better beyond x8 anyway but not sure if this is true?

Level 8

I'm very interested in this discussion too!! I have a 13900k with a 4080 OC Rog Strix, in the slots on the MB (Z790 Hero) I put 3 SSDs on the M.2_1 slot, 2 Samsung 990 Pro on the M.2_ and_3 slots, 2 crucial SSDs of 2 and 4 TB, now I would like to buy a ssd t700 pcie 5.0 to speed up startup.... although I have many doubts because currently with the 990pro I get 7500 and therefore maybe then find myself halved with gen5 due to the video card... furthermore, once the video card is mounted, in the slot pciex16 g5_1, you no longer have the space to mount the hyper rog in the pciex16 g5_2 slot (the only one to support pcie 5.0, shared with pciex16 g5_1 of the video card).
it just doesn't work!! and mount the 4080 vertically, however, I wouldn't have the necessary space for the ROG Hyper, the case is a ROG Strix Helios GX601..... huge..... but still not enough to do this operation.... otherwise a small extension.... but I don't want to ruin the aesthetics... advise me.... also another question, I have another PC still all rog with mb z390 and gaming video card 3080 oc rog strix..... i7 9700k turns on faster than the aforementioned latest generation PC........ it annoys me absurdly!!! because when it turns on the z790 hero makes a mess of controls and those damned LEDs and numbers that spin... and you waste crazy time on startup!!!!