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MAXIMUS Z790 EXTREME Dimm.2 PCIE Lanes

xenon5434
Level 7

‎01-04-2023 10:18 AM

Hi Everyone

I know this topic is not new and i read a couple older threads but there is no information on the newer boards so here is my question about the MAXIMUS Z790 EXTREME.
I read that the DIMM.2 slot uses CPU PCIE lanes wich means using them used to reduce the lanes awailable for the GPU to 8 but thats also dependant on the CPU whether it can provide more than 1x16 lanes.
As i see the 13900K has the folowing PCIE konfiguration: Up to 1x16+4, 2x8+4, this means i can install one NVME SSD on the Dimm.2 slot using 1x4 lanes and should still have 16 lanes awailable for the GPU?
Is my thinking correct or is there some other info that i am missing?
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Jlemonxx
Level 7

‎04-23-2023 01:40 AM - edited ‎04-23-2023 01:43 AM

I've had the board since launch there are many conflicting threads still to this day anyone that said they knew on the forum do not know. You can use m2_2 and m2_3 slots no downfall in gpu lanes but never m2_1 even if it's a 3.0 or 4.0 nvme now with that being said a 4090 likes to keep enabling advance power savings sometimes it'll clock as low as to say x16 1.1 which I've never seen a graphics card do that in my life lol. With all of that being said the issue was my case. Asus strix helios I removed my board and reinstalled it and it's still not able to butt flush with the rear panel. This caused my 4090 to be "straight" when I screwed it to rear thumbscrews but in fact its at a very very slight angle which caused poor contact at the slot. For weeks I struggled with this board and my gpu was stuck at x8 I tried a dozen things skimmed a ton of forums.

So you gotta make sure the pins are crystal clean gleaming and not be afraid to really plug that card in to the slot it's a beefy card so everyone stops at the light click. 

I wish I could confirm or deny about the dimm2 riser but I personally have not tried it. I have two large nvme already so maybe in the future sorry. 

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Hopper64
Level 15

‎04-23-2023 03:18 AM

I have one NVMe drive on my dimm.2 and my 4090 still operates at x16.

MZ790A Bios 2002, GSkill F5-8000J3848H16GX2-TZRK, 13900KS, EKWB D5 TBE 300, Seasonic Prime TX-1600 ATX 3.0, Asus Strix 4090 w/ Optimus block, Phanteks Enthoo Elite, Asus Claymore 2, Asus Gladius 3, Asus XG349C, Samsung 990, Windows 11 Pro
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Jlemonxx
Level 7
In response to Hopper64

‎04-23-2023 03:24 AM

This is good to hear. So what's the consensus? I have both of those nvme under my chispset heat sink. Am I good to get another nvme for the dimm2 or will it then drop lanes?

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Sorata4
Level 8
In response to Jlemonxx

‎06-12-2023 02:40 AM

I know I found this late but you only loose lanes if you place a NVME of any type in the top M.2_1 slot. That's the one covered by the LCD screen. If you place one there it goes to 8x on GPU. Place NVME in any other slot or on the DIMM Card and it will not reduce lanes.