M.2 speed limited to 3500

[Nizar77]

-Maximus xiii hero

-64G Ram

-I9 11900k

-2x Samsung 980 pro M.2

-UAD-2 quad (PCIE x2) in the third pcie slot

-No Video card yet

 

Hi All , I have question about the second M.2 speed..

I put the first M.2 in the first slot and the speed goes around 6500-7000 which is good, but today I added second M.2 in slot 3 (tried 4 also) but speed never goes above than 3500 ..according to the manual it should be also 7000.

I got the 7000 speed when I put the second M.2 in slot 2...but in this case the VGA card( which I m planing to add) will run at X8 not X16..

So is there someone has almost the some PC and components to explain what configuration I have to adjust in bios to run both M.2s at 7000 and VGA at X16?

Thanks