I am running Debian 10 kernel 4.19 and am getting 30 MB/s when writing to a tmpfs mount using this one liner:
sudo mkdir /ramdisk && sudo mount -t tmpfs -o size=2G,nodev,nosuid tmpfs /ramdisk && dd if=/dev/urandom of=/ramdisk/test bs=60k count=34000 status=progress && sudo umount /ramdisk && sudo rmdir /ramdisk
What RAM write speed are you getting on your Odyssey X85J4105 system? If you execute this RAM write test on your system, please post the result here for comparison - thank you!