Question 1TB WD_BLACK SN750 SE nvme M.2 Seq Write speed only 507 MB/S?

[TRE IzDOPE]

I have windows on a 960 EVO 250GB, and just installed this M.2, backed up windows on it, and a few games are on it. I just used AS SSD to test the speeds and the SEQ READ 2942, the SEQ WRITE 507 that is REALLY LOW? The 960 is next to my CPU in the CPU lane on my ASUS TUF gaming x570 Plus Wifi, and the WD_BLACK™ SN750 SE is at the bottom of the board that is ran by the chipset. It is in 4Lane Mode, from what I read, if I put a M.2 in the chipset slot, I can't use but only the first PCIE lane which I have a 1080 TI FTW3 on. In the settings it says you should disable write caching before benchmarking, so I did that. It has the latest firmware. Am I missing something?

 

[TRE IzDOPE]

also mention, I used the samsung magician software that came with the 960 evo. the seq read was 3340, the seq WRITE was 189!?