Does it make sense to use queue-depth when doing synchronous IO benchmark?

Does it make sense to have a queue depth > 1 when doing a synchronous IO benchmark? I was expecting the same result a of QD1, but QD32 does give better result? I thought it would just be ignored. In the fio [manual](https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-iodepth) for the option --iodepth: > Note that increasing iodepth beyond 1 will not affect synchronous ioengines... fio commands: fio --name=x --ioengine=posixaio --rw=write --bs=4k --iodepth=1 --size=512MB --fsync=1 --filename=test.img Result: 5.210 IOPS / 20MB/s fio --name=x --ioengine=posixaio --rw=write --bs=4k --iodepth=32 --size=512MB --fsync=1 --filename=test.img Result: 20.100 IOPS / 79MB/s