Why cached reads are slower than disk reads in hdparm --direct?

I am trying to interpret this result of hdparm: janus@behemoth ~ $ sudo hdparm -Tt --direct /dev/nvme0n1 /dev/nvme0n1: Timing O_DIRECT cached reads: 2548 MB in 2.00 seconds = 1273.69 MB/sec Timing O_DIRECT disk reads: 4188 MB in 3.00 seconds = 1395.36 MB/sec I do not understand how the cached reads can be slower than the direct disk reads. If I drop the --direct, I get what I would have expect: the disk reads are slower than the cached ones: janus@behemoth ~ $ sudo hdparm -Tt /dev/nvme0n1 /dev/nvme0n1: Timing cached reads: 22064 MB in 2.00 seconds = 11042.86 MB/sec Timing buffered disk reads: 2330 MB in 3.00 seconds = 776.06 MB/sec (Although it says "buffered disk reads" now). Can somebody explain to me what is going on?