Recent Wildly Fluctuating Copy Speeds of Large Files (125+ GB) to External Hard Drives

Does the target drive connected by USB have a built in cache of any type? Another user pointed out in another (similar) thread here that the speed would be high and fast for a while, until the cache was filled and, basically, back logged, while writing to the drive. So, is that WD Passport external drive a mechanical one, or an SSD, or a hybrid drive?

@johnlgalt

The WD My Passport Ultra is an external HDD. Details can be found here:

https://www.amazon.ca/WD-5Tb-My-Passport-Ultra-Portable-External-Drive/dp/B07X46C64N

I just purchased it on Amazon a month ago. I presume it does have a cache. I first noticed the speed fluctuations on the 4 TB version of my older (2019) WD My Passport Ultra about six weeks ago. I initially suspected that the drive was dying, even though it passed all of the diagnostic tests, so I ordered the new larger one.

By the way, the Seagate internal drive from which the backups are copied (Source drive) passed the Hard Disk Sentinel Pro Extended Test. I am going to run a chkdsk /r, but I don't expect any bad clusters will be found. That should eliminate the Source drive as a suspect.

Thank you for your interest in my conundrum. Have a great day.

Regards,
Phil

The chkdsk /r command, which was run this afternoon, resulted in the message that Windows found no errors on the Seagate 2 TB internal drive (D:) to which the system image backups of the C: drive Intel NVMe SSD are stored by both Macrium Reflect and Easeus Todo Backup Home, the use of which I alternate weekly.

I can only conclude the Source Drive for the backup image file copies to multiple external WD My Passport Ultra drives is NOT responsible for the wild copy speed fluctuations. Yesterday, as I reported, it passed an "Extended Surface Test" as well, and the S.M.A.R.T. data is all good for the Source drive. Hard Disk Sentinel Pro reports the Health and Performance of Drive D: to be 100%.

Something is causing these copy speed fluctuations to my external WD drives. I am open to further suggestions. I appreciate the help and advice already provided to me by the members of this Forum. Thank you.

Have a great day.

Regards,
Phil

Sorry for the late reply.

garioch7 said:

I can only conclude the Source Drive for the backup image file copies to multiple external WD My Passport Ultra drives is NOT responsible for the wild copy speed fluctuations.

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That would be a good assumption. So, more than likely it is an issue with either Windows (and specifically an update), or else the software by WD (or, if they use their own driver, then the driver itself) needs updating.

How far back do your complete system images go? If you have an idea on how far back this started happening, you could try restoring a really old image and see if the problem goes away, and then you can narrow it down to updates from that backup.

@johnlgalt

Thank you for your reply. With my newest WD drive, I never installed any of their "bloatware" on the 5 TB drive. I probably do have one backup that predates the problem, but there have been a lot of software updates on my computer in the last two months. I had another idea.

When I do my next backup, I plan to do a Selective Startup with only Microsoft services/drivers loading after the backup is completed to the internal D: drive before attempting a copy to the WD My Passport Ultra drive to see if I can eliminate a software conflict. If stable copy speed is restored, then it will be a tedious matter of trying to determine which software app(s) are causing the phenomenon.

I think that my latest idea may be more efficient. If copy speeds are stable with only Microsoft services/drivers loaded, then turn half of the apps services/drivers on for the next boot. If the problem recurs, turn off half of the apps services/drivers, and try again, etc. If all is stable with the first half, then disable that half, and enable the remaining half of the services/drivers. Rinse and repeat.

If having only the MS services/drivers loaded results in the same copy speed fluctuations, then the odds are that I have a USB hardware/driver issue or conflict.

This is not a burning issue for me. The overall copy times are the same. It is more a wanting to understand why it is happening. It is not normal behaviour, and the computer formerly did have stable copy speeds. That is why I am not frantically searching for a solution. For all we know, the Windows Updates yesterday may have solved the problem! I did run a DISM component cleanup and a /ScanHealth yesterday after the Windows updates. The latter was clean, and the former was completed successfully.

Thank you again for your continued suggestions and advice on how to diagnose this "phenomenon." It is really appreciated. Have a great day.

Regards,
Phil

garioch7 said:

When I do my next backup, I plan to do a Selective Startup with only Microsoft services/drivers loading after the backup is completed to the internal D: drive before attempting a copy to the WD My Passport Ultra drive to see if I can eliminate a software conflict. If stable copy speed is restored, then it will be a tedious matter of trying to determine which software app(s) are causing the phenomenon.

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Just realize that this may not be actually do what you think it will. Restricting certain services / drivers could help you find the problem, but could also not be of any use - because services and drivers are not necessarily tied to Windows Software updates. But, at this point, it certainly won't hurt to try.

garioch7 said:

If having only the MS services/drivers loaded results in the same copy speed fluctuations, then the odds are that I have a USB hardware/driver issue or conflict.

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• OK, so to recap - the old drive worked fine with no noticeable roller-coastering of speeds for a long time.
• Then, one day, it started roller-coastering, and continued to do so every time.
• Thinking you had an issue with that drive, you purchased a new drive, and it exhibited roller-coastering from the first use.

Does that about sum it up? If so, it definitely does seem to point to a software update of *some* sort.

One thing to consider - has any Anti-malware / anti-virus software on your system also been updated during that time?

One trick I use for offline storage is to disallow scanning of drives that I keep mostly offline, or at least particular folders within such storage, that I know I will be copying large amounts of data to / from. An example of this is to disallow Windows Defender from scanning my UUPDUMP folder where I build Windows 11 .ISOs from UUPDUMP, so that the scripts can proceed much more quickly without having Defender step in every single time to scan a file after the script has modified it.

I apologize for being remiss in not mentioning (or even thinking about) this earlier - but it is a very real possibility that your AV, even if it is just Defender, is a possible culprit as well.

@johnlgalt

Thank you for your post. Yes, you understand the problem, and it also occurs with a third WD My Passport Ultra drive.

In this post, I indicated that I did test with my security software disabled. In my first post, I identified my security software as Bitdefender Total Security (BDTS) and Malwarebytes Premium (MBP). Both are being updated on a regular basis, as are Windows and my other software applications.

That said, Bitdefender is notoriously difficult to turn off entirely. I will add exceptions for my G: drive (external) to both BDTS and MBP when I do my next backups before attempting the copy. I don't need that drive protected anyway because it is only installed to copy backup images to it. The source D: drive is already an exception or allowed.

That is an excellent suggestion. I will try that before going the msconfig route. Thank you for your valuable assistance. Have a great day. It will probably be the weekend before I do my backup. I normally do it on Friday, but I have a medical appointment some distance from where I live, so it will be delayed this week. I will keep you posted. Thanks again.

Regards,
Phil

garioch7 said:

In this post, I indicated that I did test with my security software disabled. In my first post, I identified my security software as Bitdefender Total Security (BDTS) and Malwarebytes Premium (MBP). Both are being updated on a regular basis, as are Windows and my other software applications.

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Lol my bad. I should have gone back and looked, but yeah, that exception thing might make a difference. It also might not, since any good anti-malware program should scan the file at the source prior to copying, and not be interfering with the actual copy process (and thus scanning incompletely copied files).

But stranger things have happened.

I suspect this is a dead end, but, again, better to try and eliminate it as a possibility, however remote it may be.

garioch7 said:

That is an excellent suggestion. I will try that before going the msconfig route. Thank you for your valuable assistance. Have a great day. It will probably be the weekend before I do my backup. I normally do it on Friday, but I have a medical appointment some distance from where I live, so it will be delayed this week. I will keep you posted. Thanks again.

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No worries, I try to visit here at least every other day, and as long as you're making progress (even if it is just eliminating possible culprits) it's a good thing.

Good luck with your doctor's visit, and have a great weekend, see you next week!

@johnlgalt

Your idea seemed so good that I had to try it today with last week's backup. Alas, no joy, but that possibility has been eliminated. As you say, we are slowly making progress . . .

So back to the msconfig route unless something else occurs to you. In the absence thereof, I will proceed to the Selective Startup option on the weekend and post back.

We both know it is going to be something unique to my computer configuration: hardware, or software, so this detective work could take some time.

Thanks again. Have a great day.

Regards,
Phil

garioch7 said:

So back to the msconfig route unless something else occurs to you. In the absence thereof, I will proceed to the Selective Startup option on the weekend and post back.

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Sounds like a plan.

garioch7 said:

We both know it is going to be something unique to my computer configuration: hardware, or software, so this detective work could take some time.

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Indeed. It's why I made this my career - I love this kind of investigation and fault finding. The more obscure, the better, for me.

@johnlgalt

Me too, but I prefer it when it's someone's computer that is misbehaving. That said, I like a challenge, no matter who is involved.

Will keep you posted. Thanks again so much for your time and expertise.

Have a great day.

Regards,
Phil

garioch7 said:

...but I prefer it when it's someone's computer that is misbehaving.

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So true. I had to troubleshoot why my wired network at home suddenly took a massive drop in speeds, while my wireless was fine. Wired, I was getting as low as 8-9 Mbps in both directions, which later crawled its way back up to a whopping 90 Mbps (whereas I have gigabit speed Internet). Wirelessly, I was still getting the normal 600 - 700 Mbps.

Today, after work ended, I power cycled all my networking equipment - and it seems to be working again. My wired speeds are once again where they should be, high 800s.

But that still took time, and I had to limp through the reduced speeds all day for work.

I hear you. With me, it is my wireless speeds that gradually drop for no reason. Completely recycling and rebooting the Fiber Op modem solves the problem, but it is annoying. The modem also has an annoying habit of periodically just dropping its internet connection entirely. I now reboot the beast about once a week to prevent the gradual decay in upload/download speeds. They replaced the modem eight months ago, but that just forced me to reconnect everything one by one. Evidently, it was tied to the ID of the old modem, not just to my network account and password. What a pain!

Here in rural Cape Breton, we are used to such annoyances. When I was in Port Hood, we were on "Super Slow" speed internet. It was horribly unreliable. The infrastructure was all old and decayed there. Coming here to Port Hastings and getting Fiber Op was such a bonus, if there can be such a thing after a divorce and having to sell your dream retirement home to give half of everything to the "ex."

Oh well, we are still able to sit up and take nourishment. The medical appointment is related to a bout with cancer I had ten years ago. I am still kicking. They like to put me up on the hoist annually to check out the old machine.

Thanks again for your help. Talk to you on the weekend.

Regards,
Phil

garioch7 said:

With me, it is my wireless speeds that gradually drop for no reason.

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Lol - that I would expect. Wired, though, should not fluctuate - and certainly not like that.

garioch7 said:

The modem also has an annoying habit of periodically just dropping its internet connection entirely. I now reboot the beast about once a week to prevent the gradual decay in upload/download speeds. They replaced the modem eight months ago, but that just forced me to reconnect everything one by one. Evidently, it was tied to the ID of the old modem, not just to my network account and password. What a pain!

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I get around these issues by putting in my own router behind the service provider offerings. Makes life a lot easier, and never had a problem with double NAT, either. Everything connected to the router (mesh, actually, but which I use as glorified Access Points lol). The main station connected to the Residential Gateway, as AT&T calls their device, and that connects to a separate Optical Network Terminal, or ONT. But everything works, though it is one additional step (and 3 individual satellites) to power cycle when I do have an issue like last night.

garioch7 said:

Here in rural Cape Breton, we are used to such annoyances. When I was in Port Hood, we were on "Super Slow" speed internet. It was horribly unreliable. The infrastructure was all old and decayed there. Coming here to Port Hastings and getting Fiber Op was such a bonus, if there can be such a thing after a divorce and having to sell your dream retirement home to give half of everything to the "ex."

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Haven't had to do the divorce thing, but I did build a new house 4 years ago, and my neighborhood already had fiber in it. So, I picked AT&T's FttH over Comcast's ridiculous asymmetric cable offerings (they have a fiber offering now, too, but ridiculously priced here). I can't not use a fiber connection lol. It's so much faster and much more robust for my uses.

garioch7 said:

Oh well, we are still able to sit up and take nourishment. The medical appointment is related to a bout with cancer I had ten years ago. I am still kicking. They like to put me up on the hoist annually to check out the old machine.

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Yeah, I scheduled a physical / checkup - wanted it next week. I got it set for late December lol. 2 month wait. I really hate the limitations that insurance companies place on us, but that is a topic (RANT) for another day.

Cheers!

@johnlgalt

Selective Startup, disabling all but Microsoft services, brought no joy. Full system scans (Bitdefender Total Security and Malwarebytes Premium) for malware on my computer were negative. I only usually do those once a month. Weekly, I content myself with Quick Scans unless there was reason to suspect malware, which has never happened to me. I try to practice "safe hex." Right now, I am running a Windows Defender full scan, but I doubt it will find anything.

I tried completely powering down the desktop removing the power cord, and then holding the "On" button for 30 seconds. That has solved a number of weird and wonderful issues for me and my clients over the years, but no joy.

So, I am at a loss. The overall transfer speed times are about the same. The issue is the wildly fluctuating copy speeds during the copy of large files.

When I was in msconfig, I did note that, for some reason, my computer was set to selective startup, but no unusual services were disabled. I put it back on Normal Startup, but that did not bring me any happiness either.

I guess we will have to conclude this as "Unsolved," unless you or another contributor has a possible solution. I am not going to reinstall Windows and all of my programs and data. This nuisance is just not worth all of that aggravation, particularly when all of the time and effort might turn out to be for nought. DISM and SFC scans are clean.

When I started this topic here, I thought this would be a simple issue to resolve. I thought that I must be missing something obvious. I am getting on in years, so I figured I had just forgotten something I should know, or never did learn.

Have a great weekend. Thanks for all of your suggestions and for sharing your expertise.

Regards,
Phil

garioch7 said:

So, I am at a loss. The overall transfer speed times are about the same. The issue is the wildly fluctuating copy speeds during the copy of large files.

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This suggests that a very valid possibility is that, in fact, it was always doing this but Windows Explorer (and other file transfer apps) were simply either not seeing it, or else reporting only average speed and not instantaneous speeds.

Specifically, if

garioch7 said:

The overall transfer speed times are about the same.

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Then, it might well be time to hang it up and let it do its thing, because there is no actual performance degradation here. And, I realize that you stated this before, but thus far we've been attacking the situation as if an actual problem exists, and I'm rather sure you've tackled it in as many ways possible only to see there is nothing untoward either on your system (such as Malware of any type) nor happening with your system (as in everything else works, and even the backups aren't taking any significant amount of time longer than they ever used to).

However, my conjecture above has led me to another thought, and I"m gonna try to find some relevant documentation one way or another to see if we may be on to something here, in that something so minute has been changed in the OS, but its effect is, visually, one that maybe they (Microsoft) did not account for.

@johnlgalt

Thank you for your post. What you say may well be true.

My latest idea is that perhaps the cache and/or controller chip on the Seagate drive (D:) has gone bad. I investigated yesterday and found out that Dell installed a Seagate 2 TB Barracuda drive to complement my 1 TB Intel NVMe SSD (C:). That immediately raised flags for me. Seagate is facing numerous lawsuits for certain models of the Barracuda drive. I certainly don't want to be relying on a Barracuda drive as my primary backup location, particularly one that is now four years old.

Yesterday, I ordered a 4 TB Western Digital Black internal hard drive. When it arrives and the drive caddy, I am going to install it and do my next backup to the new drive. Then I will attempt a copy to my external WD My Passport Ultra drives. If the copy speeds are stable, we have found our culprit, even though it passes S.M.A.R.T. and an extended test, which I think primarily focus on looking for bad sectors and a dying hard drive. I am not sure that testing would reveal problems with the HDD cache or controller chip.

The behaviour is consistent with the cache filling up, writing everything in a burst, and then reading again, causing the speeds to fluctuate.

I will keep you updated. If that does not fix the fluctuations, then I think that I will just have to give up and live with it.

Thank you again for your continuing interest in solving this issue. It is very much appreciated. Have a great day.

Regards,
Phil

Which Barracuda? I've had the Barracuda 7200.10, .11 and .12 series, those were nearly flawless drives. I still have them, I simply don't use them because they drain too much power and are phenomenally slower than my NVMe drives.

@johnlgalt

Drive #1 - ST2000DM008-2FR102 (ZFL0WX49) [1863 GB] D: (from AIDA Extreme 64).

Sorry to be brief, but I was hit with a nasty bug last night, and I am not at all well at the moment. I did want to acknowledge your post, though. Tried to sleep for a few hours this afternoon but just dozed.

Hopefully, I will feel a bit better tomorrow. Have a great day.

Regards,
Phil

Feel better / get well soon!