Fluctuating HDD transfer speeds

[chet_manly]

I realise this may have been answered elsewhere but I'm having issues finding an answer that anyone can agree on. I built my machine a few months ago and noticed that one of my external hard drives had a fluctuating transfer speed (going up to 30-40MB/s then dropping to 0 for 30-60secs then going back up again repeatedly). This now seems to be occurring on all my HDDs (I have 2 internal 4TB and 4 external of varying sizes - 1-2TB). When I transfer between the HDDs and the SSD my OS is on there are no issues at all with transfer speeds. I've seen a lot of places say RAM but I've run Memtest and not seen any issues with the RAM. I also figured it might be a failing hard drive but unless all 6 drives are failing at once, I find it hard to believe. I also ran chkdsk on a couple of them and found no issues, but still had the slow transfer rates between the two I tested.

All the USB drives are USB 3.0 and the internal drives are SATA III, with the exception of the SSD which is hooked up to the M.2.

Does anyone have any ideas what this might be?

 

[D_Know_WD]

Hi there chet_manly,

Well, I believe it will not hurt to test all your mechanical drives: http://www.tomshardware.co.uk/forum/282651-32-best-diagnostic-testing-utility
If there's something wrong with any of those, you can post a screenshot of the SMART report. Just upload it to an image hosting website and post the link.
Also, it would be nice to back up the data stored on it.

Apart from that, I believe it will not hurt to go to your MOBO's website and update all the drivers.

Let me know how this goes,
D_Know_WD

 

[chet_manly]

Hi D_Know_WD,

I have a few screenshots for you. Z: is showing with a caution (although I don't quite understand what the report is trying to tell me), however even if I'm trying to transfer between Y: and D:, for example, I'm experiencing the fluctuating transfer speeds.

https://1drv.ms/f/s!Ag_Z6gwHLUx-kLd7qk7cOALiiRjW-g

Chet

 

[D_Know_WD]

Well, that one is failing. You need to back up the data stored on it. There are some bad sectors on it that are already reallocated. If it is under warranty, just RMA it.

Once you back up your data, you can remove that drive and see if the fluctuating transfer speed persists. Sometimes, failing secondary drives could affect the overall system performance.

How many RAM sticks do you have? In case you have several of those, you can see what happens when you run your system with just a single RAM stick at different slots.
Are you trying to transfer a single big file?

It will really not hurt to go to your MOBO's website and update all the drivers. (especially USB 3.0 ones)

Cheers,
D_Know_WD

 

[chet_manly]

Right, I'll call in the warranty on that one. It's only a couple of months old. I haven't tried removing that drive yet but I have removed one stick of RAM (I have 2 x 8GB sticks) and it seems to have made a little difference - I'll try it in different slots now. I have noticed a something else though.

Initially I was trying to move a 50GB folder containing a lot of much smaller files (largest probably 1GB). I'm actually trying to copy my files to the internal drives and use the externals as back up until I can get a few more internals for a RAID. As I'm backing up and transfering files backwards and forwards, I've tried some smaller folders and the transfer speeds hold steady at 80 - 110MB/s up to the first GB, then it seems to drop kind of randomly after that, some times it can transfer 3GB before it drops, then it will drop again after 400MB. I don't know if that points to anything but the more information the better right?

Off to update the drivers, I'll let you know how it goes

Thanks for the help,

Chet

 

[D_Know_WD]

You can try using just the RAM stick that you've already taken out of the system after that. It's an easy way to see if one of your RAM sticks is causing troubles.
Do you have just a single, really big file. Let's say 4 - 5 gigs. It is a normal occurrence that the speed fluctuates when transferring many files, as different files could be located on different locations on the platter. (let's put it that way) Though, dropping to 0 is not really a good thing.

I believe you can run disk check and defrag on all of them. See if some of those are highly fragmented. Don't do that on your SSD.

Cheers,
D_Know_WD

 

[chet_manly]

Hi D_Know_WD,

Finally got everything backed up and took out both of the internal drives - turns out there was an issue with both of them. I've tested transferring between 2 USB 3.0 external drives, which still dropped off but not as regularly and occassionally just dropped to 20MB/s rather than 0. I then tested transferring between each drive and the SSD and there was no drop off and a steady 80MB/s.

Just as a little more information, when I was transferring between the internal and external drives to back up, if I tried to access any folders on the external drive while I was transferring data to it would knock out all my USB ports (I have a wireless keyboard and mouse which would stop working at the same time the drive disconnected and reconnected).

Cheers,

Chet

 

[D_Know_WD]

It's great you've sorted this out.

You should always get a good back up. Also, you can test the drive form time to time, so you can keep an eye on their SMART statuses.

As for the USB issue, it could be a power issue. Does this thing happen when transferring data from a healthy drive? Does this happen with any external drive? It's strange. See if something happens in Resource Monitor if something hits 100% before the disconnection.

Cheers,
D_Know_WD