New
#1
Dramatic slowdown copying two files at once
This is a problem I've had for several years now. I fully expect two file operations at a time to be slower than if run sequentially, but not this much slower. If I copy a file or group of files to (or from) my NAS I get a speed varying from over 100 megabytes per second down to 30. I can't explain why it sometimes goes at 30 instead of 100. If I launch a second operation while the first is still running, they both slow down so that the net speed is now 10 to 15 megabytes per sec. When one of the operations finishes the other does not resume at 100mb/s, it gradually increases (just averaging no doubt making it look like the speed increase is gradual) and tops out at around 10 to 30mb/s.
This behaviour has been consistent for several years and is a bit annoying. I can easily launch operations consecutively using various kludges like disk commander programs, the 'queue' option in WinRAR etc, but I wish I didn't have to. Also the random reduced speed on single file copy operations annoys me. Instead of taking a few tens of seconds to copy a file suddenly it takes a couple minutes for the same file.
The behaviour seems to occur between any of the drives in my system, from SATA hard drives to SATA2 SSD to the networked NAS. I can copy between distinct pairs of drives without a penalty, but if it's the same pair... bang... one tenth of the speed.
Only other thing I can think of that might be relevant... I also get 'kernel freezes' for a second or two if I perform big directory operations on the NAS. You usually only notice this if music is playing - there's a half-second or so pause in the music, even with VLC set to use a 5-second buffer. If you let the NAS RAID partition fill up then these pauses become irksome, like everything freezes for 30 seconds at a time. I never let it fill up these days.
The NAS is a Thecus N7700pro, SSD is a Samsung 830-series, SATA drives are mostly Seagates. Network card is "Realtek PCIe GBE Family adapter".
Motherboard is Gigabyte GA-EX58-UD4P, CPU is 6-core Intel i7 970 at 3.2GHz.
I suspect a dodgy driver for anything from mobo chipset to a disk drive or network card... no idea how to narrow it down. Also if this was 'normal' Windows 7 behaviour I would have expected to see more complaints using Google...
Quote