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Z390-F and M2_2 locked at X2 speed

SplinterSLY
Level 7

Hello everyone ! And a Happy New Year !

I just changed all my drives and I took the plunge to Windows 11 (New Year...New Drives...New Windows install...I guess...).

2 M.2 (990 PRO, one with a heatsink embedded, the other without), 1 SSD 2.5" (870 EVO) and 1 HDD 3.5" (Seagate Barracuda)

The new 2 M.2 and 1 SSD are made by Samsung, so I downloaded Samsung Magician and checked all the informations concerning my new drives, and benchmarking them to be sure everything was going fine !

I was surprised to see that the M.2 located in the M2_2 slot was slower than the one in the M2_1 slot, so I investigated, and realised that my M2_2 Slot was running at PCIe Gen.3 X2, instead of PCIe Gen.3 X4, nothing really worrying, except that, while navigating through the BIOS options, I just couldn't figure where the option to set the speed for that M2_2 slot was !

I also navigated through the forum, searching for similar problems and I found a few, more or less close to mine.

Almost all of them were simply saying that this second slot has no options to set, it's naturally working in PCIe Gen.3, at X4 ! The first slot however should have an option to chose how the drive is being used by the system.

My BIOS was quite outdated so I updated it to the very last version, thinking that the problem might have been solved later in the motherboard's life, I'm now at the very last version and…nothing has changed !

I know that, If you set the PCIe16_3 speed to X4, you lose the SATA 5 and 6 ports, and if you choose to interpret M2_1 port as SATA (instead of PCIe), you lose SATA port 1. I already knew it when I installed my setup years ago (Thank you ! Instructions Book !), that's why I plugged my other drives (1 SSD 2.5" and 1 HDD 3.5") in the SATA 3 and 4 ports. I Don't think that could have any impact on my problem but...you never know !

Maybe needless to say but I only have one graphics card, so I left third PCIe X16 on X2, since it is not used...

Does anyone has an idea concerning this specific problem ? Is there...by any luck, a way to "force it" to run at X4 ?

Before going any further, I would like to point out that I know that these M2s are designed for a PCIe 4 interface, and that my MotherBoard only has a PCIe 3 interface, but I took advantage of a nice discount, and all the advices found on the Internet made it clear that the disks would work at the maximum of what the interface could allow, so the purchase is carefully considered.

Some more informations that might help :
MB : ASUS ROG STRIX Z390-F Gaming
CPU : Intel i9-9900K
RAM : 64 GB DDR4 G.Skill Trident Z
GPU : ASUS ROG STRIX RTX 3090

Here are two screenshots of Samsung Magician, inspecting the two M.2 Drives (990 Pro is the one locked at X2 speed on slot M2_2, 990 Pro with Heatsink is working at X4 on slot M2_1). You can see that both slot can work at Gen.3 X4 max.

Screenshot_X2.pngScreenshot_X4.png

Thank you for your time and expertise !

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1 ACCEPTED SOLUTION

Accepted Solutions

SplinterSLY
Level 7

Hello again !

You're not going to believe me but...the problem's solved !

I simply unscrewed the M.2, blowed the connector a bit, replaced the M.2 and tighten the screw a bit less than before, now the problem is solved and the M.2 is working at X4 speed !

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1 REPLY 1

SplinterSLY
Level 7

Hello again !

You're not going to believe me but...the problem's solved !

I simply unscrewed the M.2, blowed the connector a bit, replaced the M.2 and tighten the screw a bit less than before, now the problem is solved and the M.2 is working at X4 speed !