Slow transfers on certain files?

[Armadillo]

Got a bit of an odd one here, that I've not come across before. Certain files are transferring slow, but only certain files.

Basically, some files on my hdd only seem to want to transfer at 30MB/s give or take, compared to others that go at 100+. These are all video files of roughly the same size. I can copy one of the slower files, then immediatly copy another file and that will go at 100, go back to the slow and that will still be 30MB/s.

I even took one of the slow transfer files, copied to the destination drive, then copied it back to the source drive in a different location. The original still only transfers at 30MB/s while the copy in a different location goes at 100+.

I've scanned the drive, health check, all shows up as fine. Drive is pretty full, are the slow files just on a part of the platter that is slow (is that even a thing)? Just windows being stupid? There doesn't seem to be any pattern to which ones seem to struggle past 30MB/s. Destination drive doesn't matter, behaviour is the same. Drive is 2TB WD green.

There's nothing important on the drive that isn't backed up, so not too worried about the drive, but it's just annoying to get random files that are so slow.

Thanks.

 

[Steampunk]

Are they big files? They could be filling buffers/caches and stalling out. There is the issue of files on slow parts of the disc. There can be quite a significant difference in speed on mechanical drives between slow and fast portions of the platters. Maybe a virus scanner is choking on files of a certain size and slowing everything down?

 

[swain90]

Seems a little strange!

Maybe try and boot your PC up with a live version of linux and try doing the copy again. If it's still doing it in linux then maybe it's the drive, however if it's not then it looks like its either a software/windows issue.

 

[bledd]

Disable your AV, try again.

 

[Armadillo]

Are they big files? They could be filling buffers/caches and stalling out. There is the issue of files on slow parts of the disc. There can be quite a significant difference in speed on mechanical drives between slow and fast portions of the platters. Maybe a virus scanner is choking on files of a certain size and slowing everything down?

All of them are around 1-2GB.

Seems a little strange!

Maybe try and boot your PC up with a live version of linux and try doing the copy again. If it's still doing it in linux then maybe it's the drive, however if it's not then it looks like its either a software/windows issue.

Disable your AV, try again.

Ok, will try both when I come across one that has slow transfer. Seems to be completely random as to which files do it, so will just have to wait until one crops up.

 

[leezer3]

As it's a spinning disk, before doing anything drastic try running a full defrag.

You'll get exactly this sort of behaviour on stupidly fragmented files

 

[Armadillo]

Thought Windows 10 was meant to defrage on schedule automatically. Last time I checked fragmentation was only 2%. I do use the drive for shadowplay recordings, so I guess maybe it's outpacing windows cleanup.

I will give it a defragment next time I have a slow file before trying anything else.

 

[Armadillo]

So came across one only going at 35MB today, an 800MB or so Shadowplay video. Tried disabling the av, defraged the drive, still only 35MB/s. I copied the file to another location on the drive, so it actually gets written elsewhere on the drive, that went at 35MB, but once the copy was made, that went at normal speed, while the original was still capped to 35MB ish. Seems like it must be where the file is on the platter. I will try linux next time.

Drive is all showing healthly with a basic smart check. Anything more in depth I should give it a once over with? Drive is down to <30GB, but I would have thought the whole drive would slow down, not just the odd file here and there.

 

[Badfish]

If they are files you downloaded then it could be that the ones you downloaded recently are in memory and files you downloaded longer ago are not in memory. So the files in memory will copy faster and the others not.

 

[sithlord]

Check Sata cables and power cables plugged in, otherwise could be bad sectors or a failing drive.

 

[Zefan]

Couldn't this just be down to location on the platter? Outside faster, inside slower?

 

[Deleted member 138126]

As @Zefan mentioned, the outside of the disk gives faster throughput than the inside, a good 30-40% difference in speed. Add fragmentation (which a full drive guarantees for large files) and there's your answer: coincidence (where the files are stored) + fragmentation.

 

[Rannoch]

Is write caching enabled?

 

[Armadillo]

Couldn't this just be down to location on the platter? Outside faster, inside slower?

As @Zefan mentioned, the outside of the disk gives faster throughput than the inside, a good 30-40% difference in speed. Add fragmentation (which a full drive guarantees for large files) and there's your answer: coincidence (where the files are stored) + fragmentation.

Actually forgot to update this.

It does seem to be this. I read online you need a decent amount of space for a proper defrag (10%ish) or it doesn't have space to shuffle stuff around and just skips stuff. Cleaned up a decent amount of space (500GB or so), gave a defrag, took a lot longer with that much free space. Since doing that, it was fine, no slow files, until today. Came across another random slow one, ran a defrag and unlike last time when it was low on space, this time it fixed it.

I knew there was a speed drop off with fragmentation and where it is on the drive platter, just never expected it to be that much. Also didn't realise you need that much space for a decent defrag, would have thought 50GB or so would be enough for windows to shuffle about.

I assume it's Shadowplay constantly fragmenting it as it's constantly recording to temporary files everytime I play. Will probably increase the frequency that windows does that drive for me.

 

[Rroff]

Was going to say about that when reading down the thread just then - sometimes for various reasons Windows can't defrag larger files.

Sometimes for that kind of use it is worth messing about with techniques like short stroking and/or multiple partitions positioned correctly on the disc for the usage.

 

[Deleted member 138126]

Thanks for the update. FYI having a full disk *massively* increases the fragmentation of every new file you place on the drive. So if you can offload a bunch of stuff to another drive, you will significantly improve your chances of staying unfragmented.

 

[chippy08]

Have the same problem on a certain folder that contains programs and a few iso images where the speed can drop to kbps but once that folder has has finished being transferred the speed will go up to to normal for all other content.

 

[TeraVirus]

I would try defragging the drive and try to defragging the large files to the end of the drive as well.

Depending on where the files are stored on the pallters, that could be the reason why some files transferred slowly. If you write them to the same area, you may have consistent speeds with all transferred files.