i install transcend 256gb pcie x4 ssd. but no appeared either at bios or at disk management. anybody can help.
Welcome to the forums!
You may want to check which G501 model that you have, but for the G501JW it sounds like there are different motherboard versions to support SATA3 or NVME M.2 SSDs as in the thread below, so you might still need to confirm that your model really supports PCIe M.2 SSDs.
Not sure if your local ASUS support or store can help at all, but if you want to send a Private Message to me at cl-Albert with your serial number, I can try to check for you.