Question 990 Pro Gen 4 NVMe SSD runs at only PCIe Gen 1 speed on Z590 Aorus Xtreme mobo - - - what’s wrong ?

[Honey97]

Hey everyone,

I’ve got a weird issue. My Gen 4 NVMe SSD Samsung 990 pro is only running at PCIe Gen 1 speeds according to CrystalDiskInfo and Samsung magician even though my setup should support Gen 4 just fine.
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Specs:
Motherboard: Gigabyte Z590 AORUS XTREME
CPU: Intel 11th Gen i9 11900k(supports PCIe Gen 4)
SSD: Samsung 990 Pro 1TB Gen 4 NVMe
OS: Windows 11 24H2
BIOS version: F15d
GPU : RX 6900xt
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What I’ve Checked:
✅ SSD is in the correct Gen 4 slot (M2P_CPU)
✅ BIOS is set to Auto/Gen4 for PCIe link speed
✅ BIOS updated
✅ CrystalDiskInfo shows PCIe 1.0 x4 or x1
✅ SSD reseated
✅ Temps are fine
✅ No PCIe risers/extenders

What Gigabyte e-support said:

> "It is normal that BIOS does not show full PCIe 4.0 speed. Please check in Windows using CrystalDiskInfo."
But I am checking in Windows — and it still says Gen 1!
Toggling setting in bios sometimes brings it to gen 4 (7000+ MBPS) with crystal disk info showings pcie gen 4 for 1 boot but in next boot it goes to Gen 1 Again (908MBPS)

Speeds according to crystal disk info

Anyone else seen this? Could this be a board issue or BIOS bug or ssd issue? Appreciate any ideas. 🙏

 

[Lutfij]

Welcome to the forums, newcomer!

Motherboard: Gigabyte Z590 AORUS XTREME
+
BIOS version: F15d
You're on the latest BIOS version, at the time of writing, while
SSD is in the correct Gen 4 slot (M2P_CPU)
also having the SSD in the slot that supports PCIe4.0x4 speeds;
https://download.gigabyte.com/FileL...e_1002.pdf?v=1ee27420caa39917c09b7cce68e418b3
per the manual.

If you flashed the BIOS to F15d recently, did you clear the CMOS after verifying your BIOS was flashed successfully? Does the SSD show up with PCIe3.0x4 speeds when populating slots M2A_SB and/or M2M_SB?

You forgot to mention the make and model of your PSU and it's age.

 

[Honey97]

Yes i did reset cmos and bios was updated as soon as it was launched, PSU is ROG STRIX 1000W, I haven't tried setting ssd to gen 3 slot yet,
Idk why it works after setting manually and resets itself

Welcome to the forums, newcomer!

Motherboard: Gigabyte Z590 AORUS XTREME
+
BIOS version: F15d
You're on the latest BIOS version, at the time of writing, while
SSD is in the correct Gen 4 slot (M2P_CPU)
also having the SSD in the slot that supports PCIe4.0x4 speeds;
https://download.gigabyte.com/FileL...e_1002.pdf?v=1ee27420caa39917c09b7cce68e418b3
per the manual.

If you flashed the BIOS to F15d recently, did you clear the CMOS after verifying your BIOS was flashed successfully? Does the SSD show up with PCIe3.0x4 speeds when populating slots M2A_SB and/or M2M_SB?

You forgot to mention the make and model of your PSU and it's age.

My PSU is ROG STRIX 1000W, bios was updated as soon as available, I have tried reseting cmos, haven't tried setting ssd on gen 3 slot yet
I don't know how it works on gen 4 speed for once and goes back to Gen 1 on next boot
https://ibb.co/bkt9jtK

Screenshot-2025-07-27-230730 hosted at ImgBB

Image Screenshot-2025-07-27-230730 hosted in ImgBB

ibb.co

https://ibb.co/JWGy21vD

Screenshot-2025-07-28-09-40-33-98-96b26121e545231a3c569311a54cda96 hosted at ImgBB

Image Screenshot-2025-07-28-09-40-33-98-96b26121e545231a3c569311a54cda96 hosted in ImgBB

ibb.co

 

[Lutfij]

but in next boot it goes to Gen 1 Again (908MBPS)
+
I don't know how it works on gen 4 speed for once and goes back to Gen 1 on next boot
Replace the CMOS battery with a fresh cell. Do you have a grounding issue in your abode?

 

[popatim]

Is your system overclocked?

 

[Honey97]

Is your system overclocked?

nope its not

but in next boot it goes to Gen 1 Again (908MBPS)
+
I don't know how it works on gen 4 speed for once and goes back to Gen 1 on next boot
Replace the CMOS battery with a fresh cell. Do you have a grounding issue in your abode?

nope no grounding issues i tried to install gigabyte app center today after which my pc crashes showing CRITICAL_PROCCESS_DIED after bsod it started again on gen 4 speed its weird [redacted], i tried pulling out my other ssds it still worked on gen 1 , now am thinking to pull out my xpg s70 blade from my ps5 to check if that ssd goes to gen1 speed too , maybe 990 pro causing that i read my reddit post many people complained about bsod using it but rarely anyone with same gen 1 problem. gonna attach screenshots of crystal disk info and magician when it ran on gen 4
https://ibb.co/8DNpGM8j

Screenshot-2025-07-29-194323 hosted at ImgBB

Image Screenshot-2025-07-29-194323 hosted in ImgBB

ibb.co

https://ibb.co/N6RNfTvM

 

[Honey97]

Update: I swapped the 990 Pro SSD with my XPG S70 Blade and it stays on Gen 4 speed with no problem, and I put the 990 Pro in gen 3, so is the 990 Pro bad then ?

 

[helper800]

Update: I swapped the 990 Pro SSD with my XPG S70 Blade and it stays on Gen 4 speed with no problem, and I put the 990 Pro in gen 3, so is the 990 Pro bad then ?

Download Samsung magician and see if there are any firmware updates for the 990 pro drive.

 

[Honey97]

Download Samsung magician and see if there are any firmware updates for the 990 pro drive.

It shows latest in Magician but Samsung have a newer version in iso format on their website.
I sent the drive to the seller for RMA.

 

[Honey97]

Download Samsung magician and see if there are any firmware updates for the 990 pro drive.

Hi @popatim i got rma and still this issue comes but i think a bit less frequent than before i made a whole video on it my video link :

View: https://www.youtube.com/watch?v=GSS6bt9AWus

similar issue form

https://forum-en.msi.com/index.php?threads/pcie-bug-with-m2_1-slot-on-x870e-tomahawk.409663/

 

[helper800]

Hi @popatim i got rma and still this issue comes but i think a bit less frequent than before i made a whole video on it my video link :

View: https://www.youtube.com/watch?v=GSS6bt9AWus

similar issue form

https://forum-en.msi.com/index.php?threads/pcie-bug-with-m2_1-slot-on-x870e-tomahawk.409663/

Yeah, I am not sure what's going on besides maybe the motherboard or CPU having issues with that particular drive. There may be some BIOS settings related to the storage device that can be tried, but other than that, I do not know what to tell you.