Assuming two systems use flash storage, network bandwidth is identical and it is configured the same way, there should be an issue within the PC, either system or storage drive. Check the system logs for errors and warning events related to data transfer from/to NAS. Try to benchmark the PCs' disks using fio to confirm they have similar performance. https://github.com/axboe/fio. Source: 11 months ago

Not specifically addressing your question, but when you get to the point of wanting to start doing some experiments you may find that 'fio' [1] is very handy. [1] https://github.com/axboe/fio. - Source: Hacker News / about 1 year ago

The dd is not a good benchmarking tool, you should use something like fio and probably tune it to use the ioengine most similar to your use case (eg. a database server will probably use some async IO interface). In your first example (with bs=1G) probably something (the guest OS, the qemu/kvm or the host OS) have split into smaller chunks anyway. Source: about 1 year ago

All linux tests are run with fio 3.32 (github) with future commit 03900b0bf8af625bb43b10f0627b3c5947c3ff79 manually applied. Source: over 1 year ago

Agree, I used flex/yacc to add an arithmetic expression evaluator to fio a few years back to allow simple math with some units in fio's job files, and for stuff like that, they're fine, but I wouldn't want to use them for a real language, the error handling is kind of a nightmare. Source: over 1 year ago

Check the fragmentation of your HD, through this defraggler. If it is above 20% perform the defragmentation of the units. Source: about 1 year ago