Is it normal for an HDD's write speeds to vary wildly?

[BrokeAFKid]

I have a 2 TB Segate Barracuda lying around that i don't use and so I arraged for somebody to come pick it up tomorrow and I wanted to make sure that it works like it should before I do that, I ran Crystaldisk mark and the results were fine but now I'm copying 40GBs of series to it and Windows is showing me very odd numbers, like the write speed will jump to 400-500 and then come back down to almost zero, stay there for a little while and then come back up. Is this normal behaviour for an HDD/is that Windows being glitchy or is there something wrong with my HDD? I unfortunately don't own any other harddrives so I can't really compare it to anything. 

[Electronics Wizardy]

Can you show a graph?

 

There is a good chance that is caching or different file sizes. I woulnd't worry if hte drive is working fine and average speed is fine.

[flibberdipper]

Could be Windows being dumb seemingly as usual with file transfers, but could also be the drive handling cache in a really idiotic way.

[TechyBen]

11 minutes ago, BrokeAFKid said:

I have a 2 TB Segate Barracuda lying around that i don't use and so I arraged for somebody to come pick it up tomorrow and I wanted to make sure that it works like it should before I do that, I ran Crystaldisk mark and the results were fine but now I'm copying 40GBs of series to it and Windows is showing me very odd numbers, like the write speed will jump to 400-500 and then come back down to almost zero, stay there for a little while and then come back up. Is this normal behaviour for an HDD/is that Windows being glitchy or is there something wrong with my HDD? I unfortunately don't own any other harddrives so I can't really compare it to anything. 

Exact model and make? Shingled drives will vary in speed. As used parts need re-read/re-write as a shingled drive uses a clever way to overlap the magnetic strips, just enough to save space and fit more data, but too much to write in a single run. So it needs to go back and redo some spots:

 

(So any data overlapping needs to be entirely written a second time when you modify/add to it.)

 

PS, also, Windows file transfer is useless. I've had drives transfer at 0.5kbps in/on Windows when large/long transfers (large or small files, but as long as it took time, it slowed down). But in Linux (still NTFS file format) transfers were 100% smooth and consistent, on the same hardware (so not a usb/cable fault).

[BrokeAFKid]

1 hour ago, Electronics Wizardy said:

Can you show a graph?

 

There is a good chance that is caching or different file sizes. I woulnd't worry if hte drive is working fine and average speed is fine.

 

This is graph that Windows is showing me. It seems like it will spike, then come back down to ~200MB/s untill that one file is copied, then tank to 0 and do the same with the next file. 

59 minutes ago, TechyBen said:

Exact model and make? Shingled drives will vary in speed. As used parts need re-read/re-write as a shingled drive uses a clever way to overlap the magnetic strips, just enough to save space and fit more data, but too much to write in a single run. So it needs to go back and redo some spots:

 

(So any data overlapping needs to be entirely written a second time when you modify/add to it.)

 

PS, also, Windows file transfer is useless. I've had drives transfer at 0.5kbps in/on Windows when large/long transfers (large or small files, but as long as it took time, it slowed down). But in Linux (still NTFS file format) transfers were 100% smooth and consistent, on the same hardware (so not a usb/cable fault).

It's this one https://www.mindfactory.de/product_info.php/2000GB-Seagate-BarraCuda-ST2000DM006-64MB-3-5Zoll--8-9cm--SATA-6Gb-s_1114927.html

I'm not sure if I understand this correctly but the drive has never been written to before today, I've had it for like 2 years but never bothered to install it lol, so I don't think it's overwriting anything. 

[TechyBen]

10 hours ago, BrokeAFKid said:

 

 

This is graph that Windows is showing me. It seems like it will spike, then come back down to ~200MB/s untill that one file is copied, then tank to 0 and do the same with the next file. 

It's this one https://www.mindfactory.de/product_info.php/2000GB-Seagate-BarraCuda-ST2000DM006-64MB-3-5Zoll--8-9cm--SATA-6Gb-s_1114927.html

I'm not sure if I understand this correctly but the drive has never been written to before today, I've had it for like 2 years but never bothered to install it lol, so I don't think it's overwriting anything. 

May just be Windows being a pain then. It does not look particularly problematic. Many things can affect transfer speed (even vibrations on the desk/fan wobble). But it seems it's just averaging out the file copy on the graph, and giving you peaks and lows between it's file allocation/segmentation or whatever (I don't know the technicalities, but my transfers sometimes do that, just because file sizes/distribution).