I built a new pc but i got problem with extremly slow Samsung 990pro speed with rtx 5090 intalled on the system!!?

[smereces]

Hi i built a new pc:

Motherboard : MSI MAG X870E TOMAHAWK WIFI

Cpu: AMD Ryzem 9 7900X

Memory: 48Gb T group

Graphic card : Rtx 5090

Hardrive : Samsung pro 990 4tb

Psu: 1200wt corsair

The problem im facing is without the rtx 5090 installed i got the normal speeds of the samsung 990pro 7800MB/s BUT when i install the rtx 5090 and i do the benchmark it give absurd slow speed of 980MB/s!!!!!!?

I have the samsung 990pro instaled in the m2_1 slot next the cpu.

Why this happend and how i can have the normal speeds of the samsung 990pro with the rtx 5090 installed!? What i need to do?

 

[Solaris17]

I’m wondering if the link rate gets reduced when a GPU is installed or if pcie 5 makes a difference on that board. I would check the manual for the pcie split diagram.