Confusing Write/Read speeds

[anotherusername]

I mostly use the QNAP to store DVD iso images. The problem I have is the random time it takes to read/write a DVD iso image to the QNAP NAS. The time is random from 18 mins to well over an hour. A 4 DVD box set took 6 hours last month. The weird thing is that if I have an upload/download to the QNAP NAS running slowly I can often just cancel it and there’s a 50% chance that it will run much faster when I do it again immediately - and I mean much faster, from 50 mins to 20 mins - just by cancelling the copy and then doing it again. I download DVDs from the QNAP to Mac when I want to watch them because sometimes the read rate isn’t fast enough to watch them over the network.

This is not my network. Other drives read/write consistently at much faster rates. I see 18Mbps WiFi (little snitch) on other apps and I can write a DVD ISO to other network discs in <15 mins. The problem is the same when I’m hardwired to the same switch as the NAS - so it's not WiFi problems. Even my PoS Buffalo NAS is much faster that the the QNAP. It’s not cables. There’s only me on the network. It’s not down to other activities (e.g. backups) - I've done tests with everything else turned off. It’s random. It happens on SMB and AFP.

Any ideas?

Thanks in advance for any help.

It’s a TS-410 with Firmware 4.2.6. Raid 5

[dolbyman]

What is the CPU usage during transfers with issues ? .. that NAS is 12 years old and will not even get close to 1GbE saturation

[anotherusername]

Hi. CPU usage during transfers is between 50 and 75%. Memory at about 60%. There's no apparent correlation between the poor write times and high CPU load.