Ultra Dual Drive m3.0 running terribly slow

So i’ve just bought a new ultra dual drive m3.0 then i format it from FAT32 to NTFS. But when i tried to copy some files there, i got only 20 MB/s transfer speed. I was expecting about 80-120 MB/s. This is botherig me a lot. How can i copy a 24GB file with those slow speed ? Even the speed drops to 50KB/s most the time. Any solution would be welcome. Thanks.