PCIe Gen 5 Not Reached on Samsung 9100 PRO in ROG Strix SCAR 18 2025

[chrisoutwright]

WD PC SN8000S 2TB and a Samsung SSD 9100 PRO 4TB. I’m aware that the laptop supports PCIe Gen 5 on both M.2 slots, so I was curious to see what kind of speeds I could get out of these drives.

The WD SN8000S is operating at PCIe Gen 3 x4 speeds (8 GB/s) (should this be? it has been part of the notebook configuration)

The Samsung 9100 PRO, however, is showing a PCIe link speed of 16,000 MB/s, indicating it's negotiating at PCIe Gen 4 x4 speeds, and not Gen5.

To rule out any slot-related limitations, I removed the WD drive completely and tested the Samsung 9100 PRO on its own.

Despite using only a single slot and ensuring maximum thermal headroom, the link speed remained at Gen 4 (16 GB/s). So, even in isolation, the 9100 PRO doesn’t negotiate beyond PCIe Gen 4 speeds.

Do I need to do anything to activate Gen5? Uninstall IRST ?

[chrisoutwright]

The Random Read seem well below what I would expect (should be  2,200K and not 1,500k)

[ElectroStingz]

Hello,

The HM870 chipset (motherboard) is Gen 4.

Your CPU is Gen 5 but 1x16 usually for the GPU and 1x4 remaining for 1 nvme slot < This means its gen 5 but only at x4 speed which = 16GB/s.

But did you try crystakdisk mark to compare to the other thread?

[Nikolay]

My system have presently two ssd - 9100 pro 2TB(main OS) and WD Black SN850X 4B -as storage only. You will see below two pictures - first one is with Crystal mark benchmark for 9100 pro and second one is benchmark from Samsung Magician software. In order to acchieve max speed of your gen 5 drive, you have to remove Bit locker protection on it. 

[Nikolay · Accepted solution]

On second picture, dated 27/05/2025, you can see benchmark of 9100pro with bitlocker enabled - similar to gen 4 speeds. Lattest one is without bit locker - double the speed.