Wow! Is it only ext4 vs ext3?

[FcbInfo]

Have installed Proxmox with normal prompt and after I have used boot: linux ext4 on installation.

Results:

With normal prompt:

[root@srv]# dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
16384+0 records in
16384+0 records out
1073741824 bytes (1.1 GB) copied, 4.522076 s, 237 MB/s

With linux ext4 prompt:

[root@srv]# dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync
16384+0 records in
16384+0 records out
1073741824 bytes (1.1 GB) copied, 2.38004 s, 451 MB/s

Same server, same hdd. Difference is only the EXT4 at boot!